Endangered and Threatened Wildlife and Plants; Removing the Kirtland's Warbler From the Federal List of Endangered and Threatened Wildlife

Cited as:84 FR 54436
Court:Fish And Wildlife Service
Publication Date:09 Oct 2019
Record Number:2019-22096
Federal Register, Volume 84 Issue 196 (Wednesday, October 9, 2019)
[Federal Register Volume 84, Number 196 (Wednesday, October 9, 2019)]
                [Rules and Regulations]
                [Pages 54436-54463]
                From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
                [FR Doc No: 2019-22096]
                [[Page 54435]]
                Vol. 84
                Wednesday,
                No. 196
                October 9, 2019
                Part V
                Department of the Interior
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                Fish and Wildlife Service
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                50 CFR Part 17
                Endangered and Threatened Wildlife and Plants; Removing the Kirtland's
                Warbler From the Federal List of Endangered and Threatened Wildlife;
                Final Rule
                Federal Register / Vol. 84 , No. 196 / Wednesday, October 9, 2019 /
                Rules and Regulations
                [[Page 54436]]
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                DEPARTMENT OF THE INTERIOR
                Fish and Wildlife Service
                50 CFR 17
                [Docket No. FWS-R3-ES-2018-0005; FXES11130900000]
                RIN 1018-BC01
                Endangered and Threatened Wildlife and Plants; Removing the
                Kirtland's Warbler From the Federal List of Endangered and Threatened
                Wildlife
                AGENCY: Fish and Wildlife Service, Interior.
                ACTION: Final rule.
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                SUMMARY: Under the authority of the Endangered Species Act of 1973, as
                amended (ESA), we, the U.S. Fish and Wildlife Service (Service), are
                removing the Kirtland's warbler (Setophaga kirtlandii) from the Federal
                List of Endangered and Threatened Wildlife (List) due to recovery. This
                determination is based on a thorough review of the best available
                scientific and commercial information, which indicates that the threats
                to the species have been eliminated or reduced to the point that the
                species has recovered and no longer meets the definition of endangered
                or threatened under the ESA. This rule also announces availability of a
                post-delisting monitoring plan for Kirtland's warbler.
                DATES: This rule is effective November 8, 2019.
                ADDRESSES: This final rule and the post-delisting monitoring plan are
                available on the internet at http://www.regulations.gov under Docket
                No. FWS-R3-ES-2018-0005 or https://ecos.fws.gov. Comments and materials
                we received, as well as supporting documentation we used in preparing
                this rule, are available for public inspection at http://www.regulations.gov. Comments, materials, and documentation that we
                considered in this rulemaking will be available by appointment, during
                normal business hours at: U.S. Fish and Wildlife Service, Michigan
                Ecological Services Field Office, 2651 Coolidge Road, Suite 101, East
                Lansing, MI 48823; telephone 517-351-2555.
                FOR FURTHER INFORMATION CONTACT: Scott Hicks, Field Supervisor,
                Michigan Ecological Services Field Office, 2651 Coolidge Road, Suite
                101, East Lansing, MI 48823; telephone 517-351-2555. If you use a
                telecommunications device for the deaf (TDD), please call the Federal
                Relay Service at 800-877-8339.
                SUPPLEMENTARY INFORMATION:
                Executive Summary
                    Why we need to publish a rule. Under the Endangered Species Act, a
                species may be removed from the List (``delisted'') if it is determined
                that it has recovered and is no longer endangered or threatened.
                Delisting can be completed only by issuing a rule.
                    This rule removes the Kirtland's warbler (Setophaga kirtlandii)
                from the List.
                    Basis for action. Under the ESA, we determine that a species is an
                endangered or threatened species based on any of five factors: (A) The
                present or threatened destruction, modification, or curtailment of its
                habitat or range; (B) overutilization for commercial, recreational,
                scientific, or educational purposes; (C) disease or predation; (D) the
                inadequacy of existing regulatory mechanisms; or (E) other natural or
                manmade factors affecting its continued existence. We must consider the
                same factors in delisting a species. We have determined that the
                primary threats to the Kirtland's warbler have been reduced or managed
                to the point that the species is recovered.
                    Peer review and public comment. We sought comments on the proposed
                delisting rule and draft post-delisting monitoring plan from
                independent specialists to ensure that this rule is based on
                scientifically sound data, assumptions, and analyses. We also
                considered all comments and information we received during the proposed
                delisting rule's comment period.
                Previous Federal Actions
                    On April 12, 2018, we published a proposed rule to remove
                Kirtland's warbler from the List (83 FR 15758). Please refer to that
                proposed rule for a detailed description of previous Federal actions
                concerning this species.
                Species Information
                Taxonomy
                    The Kirtland's warbler is a songbird classified in the Order
                Passeriformes, Family Parulidae. This species was originally described
                in 1852, and named Sylvicola kirtlandii (Baird 1872, p. 207). The
                American Ornithologists' Union Committee on Classification and
                Nomenclature-North and Middle America recently changed the
                classification of the Parulidae, which resulted in three genera
                (Parula, Dendroica, and Wilsonia) being deleted and transferred to the
                genus Setophaga (Chesser et al. 2011, p. 606). This revision was
                adopted by the Service on February 12, 2014 (78 FR 68370; November 14,
                2013).
                Distribution
                    The Kirtland's warbler is a neotropical migrant that breeds in jack
                pine (Pinus banksiana) forests in northern Michigan, Wisconsin, and
                Ontario. This species has one of the most geographically restricted
                breeding distributions of any mainland bird in the continental United
                States. Breeding habitat within the jack pine forest is both highly
                specific and disturbance-dependent, and likely was always limited in
                extent (Mayfield 1960, pp. 9-10; Mayfield 1975, p. 39). Similarly, the
                known wintering range is primarily restricted to The Bahamas (Cooper et
                al. 2019, p. 83).
                    Kirtland's warblers are not evenly distributed across their
                breeding range. Female Kirtland's warblers are often observed with
                singing males; therefore, nesting is generally assumed to occur at most
                sites where singing males are present (Probst et al. 2003, p. 369;
                MDNR, USFWS, USFS, unpubl. data). More than 98 percent of all singing
                males have been counted in the northern Lower Peninsula of Michigan
                since population monitoring began in 1951 (Michigan Department of
                Natural Resources (MDNR), Service (USFWS), U.S. Forest Service (USFS),
                unpubl. data). The core of the Kirtland's warbler's breeding range is
                concentrated in five counties in northern lower Michigan (Ogemaw,
                Crawford, Oscoda, Alcona, and Iosco), where nearly 85 percent of the
                singing males were recorded between 2000 and 2015, with over 30 percent
                counted in Ogemaw County alone and over 21 percent in just one township
                during that same time period (MDNR, USFWS, USFS, unpubl. data).
                    Kirtland's warblers have been observed in Ontario periodically
                since 1900 (Samuel 1900, pp. 391-392) and in Wisconsin since the 1940s
                (Hoffman 1989, p. 29). Systematic searches for the presence of
                Kirtland's warblers in States and provinces adjacent to Michigan,
                however, did not begin until 1977 (Aird 1989, p. 32; Hoffman 1989, p.
                1) and have not been conducted consistently across the years. Shortly
                after these searches began, male Kirtland's warblers were found during
                the breeding season in Ontario in 1977 and Quebec in 1978 (Aird 1989,
                pp. 32-35), Wisconsin in 1978 (Tilghman 1979, p. 19), and the Upper
                Peninsula of Michigan in 1982 (Probst 1985, p. 11). Nesting was
                confirmed in the Upper Peninsula in 1996 (Weinrich 1996, p. 2; Weise
                and Weinrich 1997, p. 2), and in Wisconsin and Ontario in 2007 (Richard
                2008, pp. 8-10; Trick et al. 2008, pp. 97-98). Singing males have been
                observed in the
                [[Page 54437]]
                Upper Peninsula annually since 1993, with the majority of observations
                in the central and eastern Upper Peninsula (MDNR, USFWS, USFS, unpubl.
                data). In Wisconsin, nesting has been confirmed in Adams County every
                year since 2007 and has expanded into Marinette and Bayfield Counties
                (USFWS 2017, pp. 2-4). Scattered observations of mostly solitary birds
                have also occurred in recent years at several other sites in Douglas,
                Vilas, Washburn, and Jackson Counties in Wisconsin. Similarly, in
                Ontario, nesting was confirmed in Renfrew County from 2007 to 2016
                (Richard 2013, p. 152; Tuininga 2017, pers. comm.), and reports of
                Kirtland's warblers present during the breeding season have occurred in
                recent years in both northern and southern Ontario (Tuininga 2017,
                pers. comm.).
                    The current distribution of breeding Kirtland's warblers
                encompasses the known historical breeding range of the species based on
                records of singing males observed in Michigan's northern Lower
                Peninsula, Wisconsin, and Ontario (Walkinshaw 1983, p. 23). In
                Michigan's northern Lower Peninsula, the Kirtland's warbler's breeding
                habitat is spread over an approximately 15,540-square-kilometer (km)
                (6,000-square-mile) non-contiguous area. In 2015, the number of singing
                males confirmed in Wisconsin (19), Ontario (20), and the Upper
                Peninsula (37) represented approximately 3 percent of the total singing
                male population (Environment Canada, MDNR, USFS, USFWS, Wisconsin
                Department of Natural Resources (WDNR), unpubl. data), demonstrating
                the species' reliance on their core breeding range in Michigan's
                northern Lower Peninsula. The number of Kirtland's warblers that could
                ultimately exist outside of the core breeding range is unknown;
                however, these peripheral individuals do contribute to a wider
                distribution.
                    On the wintering grounds, Kirtland's warblers are more difficult to
                detect and are infrequently observed. Kirtland's warblers are unevenly
                distributed across the landscape; they tend to hide in low-lying, dense
                vegetation, and males do not generally sing during the winter (Currie
                et al. 2003, pp. 1-2; Currie et al. 2005a, p. 97). Kirtland's warblers
                winter largely within The Bahamas (Mayfield 1996, pp. 36-38; Lee et al.
                1997, p. 21; Stone 1986, p. 2). The Bahamas is an archipelago of
                approximately 700 low-lying islands stretching more than 1,046 km (650
                miles) from near the eastern coast of Florida to the southeastern tip
                of Cuba. The central islands, particularly Eleuthera and Cat Islands,
                support the largest known population of wintering Kirtland's warblers
                (Sykes and Clench 1998, pp. 249-250; Cooper et al. 2019, p. 85).
                Wintering Kirtland's warbler have also been observed in The Bahamas on
                The Abacos, Andros, Cat Island, Crooked Island, Eleuthera, The Exumas,
                Grand Bahama Island, Long Island, and San Salvador (Blanchard 1965, pp.
                41-42; Cooper, unpubl. data; Cooper et al. 2019, p. 85; Ewert and
                Wunderle, unpubl. data; Haney et al. 1998, p. 202; Hundley 1967, pp.
                425-426; Jones et al. 2013, pp. 638-641; Mayfield 1972, pp. 347-348;
                Mayfield 1996, pp. 37-38; Sykes and Clench 1998, p. 250).
                    Although the central islands of The Bahamas support the greatest
                number of overwintering Kirtland's warblers, less frequent sightings
                have been reported elsewhere in the Caribbean, including sightings from
                northern Dominican Republic, coastal Mexico (Haney et al. 1998, p.
                205), Bermuda (Amos 2005, p. 3), Cuba (Isada 2006, p. 462; Sorenson and
                Wunderle 2017), Florida (Cooper et al. 2019, p. 85), and Jamaica
                (Weidensaul 2019). These sightings may represent vagrants and do not
                necessarily represent an extension of the overwintering range.
                    Recent data from winter playback surveys, citizen scientists, and
                light-level geolocators also indicate that the majority of
                overwintering Kirtland's warblers are found in the central Bahamas,
                with fewer birds overwintering in the western and eastern Bahamas and
                Cuba (Cooper et al. 2017, pp. 209-211; Cooper et al. 2019, pp. 84-85).
                    Although the central islands of The Bahamas support the greatest
                number of overwintering Kirtland's warblers, less frequent sightings
                have been reported elsewhere in the Caribbean. Of 107 accessible
                reports, only 3 originated from outside of The Bahamas: Two sightings
                from northern Dominican Republic, and one sighting from coastal Mexico
                (Haney et al. 1998, p. 205). In addition, recent winter reports of
                solitary individuals have originated from Bermuda (Amos 2005, p. 3),
                Cuba (Isada 2006, p. 462; Sorenson and Wunderle 2017), Florida (Cooper
                et al. 2019, p. 85), and Jamaica (Weidensaul 2019), possibly
                representing vagrants and not necessarily representative of an
                extension of the overwintering range.
                    Although the known wintering range appears restricted primarily to
                The Bahamas, many of the islands in the Caribbean basin are uninhabited
                by people, may be overgrown and difficult to access, or have had
                limited avian survey efforts, which may constrain our ability to
                comprehensively describe the species' wintering distribution.
                Kirtland's warblers readily shift sites on the wintering grounds based
                on habitat availability and food resources, and they colonize new areas
                following disturbance (Wunderle et al. 2007, p. 123; Wunderle et al.
                2010, p. 134; Wunderle et al. 2014, p. 44). Suitable habitat may exist
                on other islands, both within The Bahamas and elsewhere in the
                Caribbean basin, potentially providing habitat and buffering against
                the effects of catastrophic events such as hurricanes. However, the
                full extent and availability of suitable habitat on the wintering
                grounds has not been measured outside of the more-studied island of
                Eleuthera (Wunderle 2018, pers. comm.).
                Breeding Habitat
                    The Kirtland's warbler's breeding habitat consists of jack pine-
                dominated forests with sandy soil and dense ground cover (Walkinshaw
                1983, p. 36), most commonly found in northern lower Michigan, with
                scattered locations in the Upper Peninsula of Michigan, Wisconsin, and
                Ontario. Jack pine-dominated forests of the northern Great Lakes region
                historically experienced large, frequent, and catastrophic stand-
                replacing fires (Cleland et al. 2004, p. 313). These fires occurred
                approximately every 60 years, burned approximately 85,420 hectares (ha)
                (211,077 acres (ac)) per year, and resulted in jack pine comprising 53
                percent of the total land cover (Cleland et al. 2004, pp. 315-317).
                Modern wildfire suppression has since increased the average fire return
                interval within this same landscape to approximately 775 years,
                decreased the amount of area burned to approximately 6,296 ha (15,558
                ac) per year, and reduced the contribution of jack pine to 37 percent
                of the current land cover (Cleland et al. 2004, p. 316). The overall
                effect has been a reduction in the extent of dense jack pine forest,
                and in turn, the Kirtland's warbler's breeding habitat.
                    Kirtland's warblers generally occupy jack pine stands that are 5 to
                23 years old and at least 12 ha (30 ac) in size (Donner et al. 2008, p.
                470). The most obvious difference between occupied and unoccupied
                stands is the percent canopy cover (Probst 1988, p. 28). Stands with
                less than 20 percent canopy cover are rarely used for nesting (Probst
                1988, p. 28). Tree canopy cover reflects overall stand structure,
                combining individual structural components such as tree stocking,
                spacing, and height factors (Probst 1988, p. 28). Tree canopy cover,
                therefore, may be an important environmental cue for Kirtland's
                warblers when selecting nesting areas.
                [[Page 54438]]
                    Occupied stands usually occur on dry, excessively drained,
                nutrient-poor glacial outwash sands (Kashian et al. 2003, pp. 151-153).
                Stands are structurally homogeneous with trees ranging 1.7 to 5.0
                meters (m) (5.5 to 16.4 feet (ft)) in height and are generally of three
                types: Wildfire-regenerated, planted, and unburned-unplanted (Probst
                and Weinrich 1993, p. 258). Wildfire-regenerated stands occur naturally
                following a stand-replacing fire from serotinous seeding (seed cones
                remain closed on the tree with seed dissemination in response to an
                environmental trigger, such as fire). Planted stands are stocked with
                jack pine saplings after a clear cut. Unburned-unplanted stands
                originate from clearcuts that regenerate from non-serotinous, natural
                seeding, and thus do not require fire to release seeds.
                    Optimal habitat is characterized as large stands (more than 32 ha
                (80 ac)) composed of 8- to 20-year-old jack pines that regenerated
                after wildfires, with 27 to 60 percent canopy cover, and more than
                5,000 stems per hectare (2,023 stems per acre) (Probst and Weinrich
                1993, pp. 262-263). The poor quality and well-drained soils reduce the
                risk of nest flooding and maintain low shrubs that provide important
                cover for nesting and brood-rearing. Yet as jack pine saplings grow in
                height, percent canopy cover increases, causing self-pruning of the
                lower branches and changes in light regime, which diminishes cover of
                small herbaceous understory plants (Probst 1988, p. 29; Probst and
                Weinrich 1993, p. 263; Probst and Donnerwright 2003, p. 331).
                Kirtland's warblers select nest sites with higher jack pine densities,
                higher percent cover of blueberry, and lower percent cover of woody
                debris than would be expected if nests were placed at random (Bocetti
                1994, p. 122). Due to edge effects associated with low area-to-
                perimeter ratios, predation rates may be higher for Kirtland's warblers
                nesting in small patches bordered by mature trees than in large patches
                (Probst 1988, p. 32; Robinson et al. 1995, pp. 1988-1989; Helzer and
                Jelinski 1999, p. 1449). Foraging requirements may also be negatively
                influenced as jack pines mature (Fussman 1997, pp. 7-8).
                    Conversely, marginal habitat is characterized as jack pine stands
                with at least 20 to 25 percent tree canopy cover and a minimum density
                of 2,000 stems per hectare (809 stems per acre, Probst and Weinrich
                1993, pp. 261-265; Nelson and Buech 1996, pp. 93-95), and is often
                associated with unburned-unplanted areas (Donner et al. 2010, p. 2).
                The main disadvantage of marginal habitat is reduced pairing success
                (Probst and Haynes 1987, p. 237); however, Kirtland's warblers
                successfully reproduce in areas with smaller percentages of jack pine
                and with significant components of red pine (Pinus resinosa) and pin
                oak (Quercus palustris) in Wisconsin and Canada (Mayfield 1953, pp. 19-
                20; Orr 1975, pp. 59-60; USFWS 1985, p. 7; Fussman 1997, p. 5; Anich et
                al. 2011, p. 201; Richard 2013, p. 155; Richard 2014, p. 307). Use of
                these areas in Michigan is rare and occurs for only short durations
                (Huber et al. 2001, p. 10). In Wisconsin, however, breeding has
                occurred primarily in red pine plantations that have experienced
                extensive red pine mortality and substantial natural jack pine
                regeneration (Anich et al. 2011, p. 204). Preliminary investigation
                (Anich et al. 2011, p. 204) suggests that, in this case, a matrix of
                openings and thickets has produced conditions suitable for Kirtland's
                warblers, and that the red pine component may actually prolong the use
                of these sites due to a longer persistence of low live branches on red
                pines. Habitat conditions in documented Kirtland's warbler breeding
                areas in Ontario had ground cover similar to breeding sites in Michigan
                and Wisconsin, although tree species composition was more similar to
                Wisconsin sites than Michigan sites (Richard 2014, p. 306). The tree
                species composition at the Canadian sites also had high levels of red
                pine (up to 71 percent), similar to the plantations in Wisconsin (Anich
                et al. 2011, p. 201; Richard 2014, p. 307).
                    Habitat management to benefit Kirtland's warblers began as early as
                1957 on State forest land and 1962 on Federal forest land (Mayfield
                1963, pp. 217-219; Radtke and Byelich 1963, p. 209). Efforts increased
                in 1981, with the establishment of an expanded habitat management
                program to supplement wildfire-regenerated habitat and ensure the
                availability of relatively large patches of early successional jack
                pine forest for nesting (Kepler et al. 1996, p. 16). In the late 1980s,
                maturation of habitat generated through wildfire contributed to a
                higher percentage of the total suitable habitat available to the
                Kirtland's warbler compared to other types of habitat (Donner et al.
                2008, p. 472). By 1992, artificially regenerated plantation habitat was
                nearly twice as abundant as wildfire habitat, and increased to triple
                that of wildfire habitat by 2002 (Donner et al. 2008, p. 472). From
                1979 to 1994, the majority of singing males were found in wildfire-
                generated habitat (Donner et al. 2008, p. 474). By 1994, responding to
                a shift in available nesting habitat types, males redistributed out of
                habitat generated by wildfire and unburned-unplanted habitat and into
                plantation (planted) habitat. From 1995 to 2004, males continued
                redistributing into plantations from wildfire habitat, and 85 percent
                of males were found in plantation habitat by 2004 (Donner et al. 2008,
                p. 475). This redistribution of males into plantations also resulted in
                males being more evenly distributed across the core breeding range than
                in previous years. Since 2004, the majority of Kirtland's warblers
                continue to nest in plantations (USFWS, unpubl. data).
                    The amount of available suitable habitat has also increased
                significantly in the past 40 years due to these increased efforts by
                land management agencies. The goal for 51,638 ha (127,600 ac) of
                available habitat to support a recovered Kirtland's warbler population
                was initially set out in the 1981 Management Plan for Kirtland's
                Warbler Habitat (USFS and MDNR 1981, p. 18). Of this total,
                approximately 29,987 ha (74,100 ac) of Michigan State forest lands and
                about 21,650 ha (53,500 ac) of Federal forest lands were identified as
                lands suitable and manageable for Kirtland's warbler breeding habitat.
                That plan also provided prescriptions and guidelines to be used in
                protecting and improving identified nesting habitat. Contiguous stands
                or stands in close proximity were grouped into 23 areas referred to as
                Kirtland's Warbler Management Areas (KWMAs). KWMAs are administrative
                boundaries that describe parcels of land dedicated to and managed for
                Kirtland's warbler breeding habitat. The KWMAs were further subdivided
                into cutting blocks containing 200 or more acres of contiguous stands.
                These acreages were determined by factoring an average population
                density of one breeding pair per 12 ha (30 ac) into a 45- to 50-year
                commercial harvest rotation, with the goals of producing suitable
                habitat as well as marketable timber (USFWS 1985, p. 21). Data
                collected from the annual singing male census from 1980 to 1995
                indicated that a breeding pair used closer to 15 ha (38 ac) within
                suitably aged habitat (Bocetti et al. 2001, p. 1). Based on these data,
                in 2002, the Kirtland's Warbler Recovery Team (Recovery Team)
                recommended increasing the total amount of managed habitat to 76,890 ha
                (190,000 ac) (Ennis 2002, p. 2). Habitat management is currently
                conducted on approximately 88,788 ha (219,400 ac) of jack pine forest
                within MDNR (36,705 ha (90,700 ac)), USFS (49,372 ha; 122,000 ac), and
                Service lands (2,711 ha (6,700 ac)) throughout the northern Lower
                [[Page 54439]]
                Peninsula and Upper Peninsula of Michigan (MDNR et al. 2015, pp. 22-
                23), exceeding both the original and revised acreage goals.
                Wintering Habitat
                    On the wintering grounds, Kirtland's warblers occur in early
                successional scrublands, characterized by dense, low, broadleaf shrubs
                of varied foliage layers with small openings, resulting from natural or
                anthropogenic disturbances (locally known as low coppice) (Maynard
                1896, pp. 594-595; Challinor 1962, p. 290; Mayfield 1972, p. 267;
                Radabaugh 1974, p. 380; Mayfield 1992, p. 3; Mayfield 1996, pp. 38-39;
                Lee et al. 1997, p. 23; Haney et al. 1998, p. 207; Sykes and Clench
                1998, p. 256; Wunderle et al. 2007, p. 123; Wunderle et al. 2010, p.
                133). Kirtland's warblers predominantly overwinter in broadleaf scrub
                habitat, rather than pine-dominated habitats (Cooper et al. 2019, p.
                83). Suitable wintering habitat requires availability of a food source,
                often fruit plants such as Erithalis fruticosa and Lantana involucrata
                (see ``Diet and Foraging,'' below, for additional discussion) that are
                in fruit at the right time of year, as well as availability of water.
                    Historically, Kirtland's warbler winter habitat was likely created
                when storm surges or other natural disturbances, such as wildfire,
                removed vegetation and leaf litter (Wunderle and Ewert 2018, p. 1;
                Wunderle 2018, pers. comm.), allowing for establishment of the
                preferred fruit plants (which are shade-intolerant) (Fleming et al.
                2015, p. 588). Human-caused disturbances may also produce suitable
                habitat for Kirtland's warblers. Although goats consume the preferred
                fruit plants, the plants readily regrow in open sunlight and persist,
                indicating goat grazing could be an effective means of setting back
                succession and creating or maintaining Kirtland's warbler habitat
                (Fleming et al. 2016, p. 287). Abandonment of garden plots or other
                cultivated lands are not likely to result in suitable Kirtland's
                warbler habitat, because the important fruit plants are shaded out by
                other, faster-growing plants (Wunderle et al., unpubl. data).
                    Kirtland's warblers typically occupy wintering sites 3 to 28 years
                (the mean is approximately 14 years) after human disturbance (Wunderle
                et al. 2010, p. 127). As local food resources diminish in abundance,
                these sites may not be sufficient to sustain an individual for an
                entire winter; therefore, individuals must move widely from patch to
                patch, tracking changes in fruit abundance (Wunderle et al. 2007, p.
                123; Wunderle et al. 2010, p. 134; Wunderle et al. 2014, p. 44).
                Migration and Stopover Habitat
                    Spring departure from the wintering grounds is estimated to occur
                from late April to early May, and arrival on the breeding grounds
                occurs approximately 15 days later (Cooper et al. 2017, p. 212;
                Rockwell et al. 2012, p. 746; Ewert et al. 2012, p. 11). Male
                Kirtland's warblers have been observed arriving on the breeding grounds
                between May 1 and June 5 (Petrucha 2011, p. 17; Rockwell et al. 2012,
                p. 747), with the first females arriving a week or so after the first
                males (Mayfield 1960, pp. 41-42; Rockwell 2013, pp. 48-49).
                    Fall migration of adult males begins in late September through late
                October and ends with arrival on the wintering grounds in mid-October
                to early November (Cooper et al. 2017, p. 212). The earliest recorded
                sighting in The Bahamas was August 20 (Robertson 1971, p. 48). Data
                from recovered geolocators showed that most Kirtland's warblers
                exhibited a loop migration, with fall migration occurring farther east
                than spring migration (Cooper et al. 2017, p. 214). Nearly all males
                departed the breeding grounds and flew in an easterly direction,
                spending time in southeastern Ontario or in the eastern Great Lakes
                region of the United States (Cooper et al. 2017, pp. 211, 213). Fall
                migration proceeded in a general southern direction, departing the
                mainland United States along the Carolina coastline (Cooper et al.
                2017, pp. 211, 213). Spring migration followed a more westerly path,
                with landfall occurring in Florida and Georgia (Cooper et al. 2017, pp.
                213, 216). An additional stopover site was identified in the western
                Lake Erie basin (Cooper et al. 2017, p. 216). An analysis of 562
                records of Kirtland's warblers observed during migration found that
                migration records were spread over most of the United States east of
                the Mississippi River, clustered around the Great Lakes and Atlantic
                Ocean coastlines (Petrucha et al. 2013, p. 383).
                    Migrating Kirtland's warblers have been observed in a variety of
                habitats, including shrub/scrub, residential, park, orchard, woodland,
                and open habitats (Petrucha et al. 2013, p. 390). There is some
                evidence that dense vegetation less than 1.5 m (4.9 ft) in height may
                be important to migrating Kirtland's warblers (Stevenson and Anderson
                1994, p. 566). The majority of migration records (82 percent) described
                the habitat as shrub/scrub, similar in structure to what the species
                uses on the breeding and wintering grounds (Petrucha et al. 2013, p.
                384).
                Diet and Foraging
                    On the breeding grounds, Kirtland's warblers are primarily
                insectivorous and forage by gleaning (plucking insects from) pine
                needles, leaves, and ground cover, occasionally making short sallies,
                hover-gleaning at terminal needle clusters, and gathering flying
                insects on the wing. Kirtland's warblers forage on a wide variety of
                prey items, including various types of larvae, moths, flies, beetles,
                grasshoppers, ants, aphids, spittlebugs, and blueberries (Mayfield
                1960, pp. 18-19; Fussman 1997, p. 33). Similar taxa have been
                identified from fecal samples from Kirtland's warblers, although
                homopterans (primarily spittlebugs), hymenopterans (primarily ants),
                and blueberries were proportionally greater in number than other taxa
                among samples collected from July to September (Deloria-Sheffield et
                al. 2001, p. 385). These differences in the relative importance of food
                items between spring foraging observations and late summer fecal
                samples may be temporal and may reflect a varied diet that shifts as
                food items become more or less available during the breeding season
                (Deloria-Sheffield et al. 2001, p. 386). Within nesting areas,
                arthropod numbers peak at the same time that most first broods reach
                the fledging stage (Fussman 1997, p. 27). Planted and wildfire-
                regenerated habitats were extremely similar in terms of arthropod
                diversity, abundance, and distribution, suggesting that current habitat
                management techniques are effective in simulating the effects that
                wildfire has on food resources for Kirtland's warblers (Fussman 1997,
                p. 63).
                    On the wintering grounds, Kirtland's warblers rely on a mixed diet
                of fruit and arthropods. During foraging observations, 69 percent of
                Kirtland's warblers consumed fruits, such as snowberry (Chiococca
                alba), wild sage (Lantana involucrata), and black torch (Erithalis
                fruticosa), with wild sage being the overwhelmingly predominant food
                choice (Wunderle et al. 2010, pp. 129-130). Despite variation in food
                availability among sites and winters, the proportion of fruit and
                arthropods in fecal samples of Kirtland's warblers was consistent
                (Wunderle et al. 2014, p. 25). Food abundance was a reliable predictor
                of site fidelity, with birds shifting location to sites with higher
                biomass of ripe fruit and ground arthropods during the late winter
                (Wunderle et al. 2014, p. 31).
                Demographics
                    The average life expectancy of adult Kirtland's warblers is
                approximately 2.5
                [[Page 54440]]
                years (Walkinshaw 1983, pp. 142-143). The oldest Kirtland's warbler on
                record was an 11-year-old male, which, when recaptured in the Damon
                KWMA in 2005, appeared to be in good health and paired with a female
                (USFS, unpubl. data).
                    Overall, Kirtland's warbler annual survival estimates are similar
                to those of other wood warblers (reviewed in Faaborg et al. 2010, p.
                12). Survival rates of the Kirtland's warbler varied by sex and age
                classes (Mayfield 1960, pp. 204-207; Walkinshaw 1983, pp. 123-143;
                Bocetti et al. 2002, p. 99; Rockwell et al. 2017, p. 723; Trick,
                unpubl. data). Based on mark-recapture data from 2006-2010 on breeding
                grounds in Michigan and from 2003-2010 on the wintering grounds in The
                Bahamas, the mean annual survival estimates for adults and yearlings
                were 0.58 and 0.55, respectively (Rockwell et al. 2017, pp. 719-721).
                Monthly survival probabilities were relatively high when birds were
                stationary on the wintering and breeding grounds, and were
                substantially lower during the migratory period, which has the highest
                mortality rate out of any phase of the annual cycle, accounting for 44
                percent of annual mortality (Rockwell et al. (2017, p. 722). Survival
                probability was positively correlated to March rainfall in the previous
                year, suggesting the effects of rain on the wintering grounds carried
                over to affect annual survival in subsequent seasons. Late winter
                rainfall in The Bahamas showed a positive effect on Kirtland's warblers
                corrected body mass (Wunderle et al. 2014, p. 47). Reduced rain can
                result in lower available food resources for Kirtland's warblers, which
                could result in poorer body condition, making them less likely to
                survive the subsequent spring migration (Rockwell et al. 2017, pp. 721-
                722) and lowering reproductive success during the breeding season
                (Rockwell et al. 2012, p. 745).
                    Historically, one of the largest factors influencing Kirtland's
                warbler's reproductive success was brood parasitism from brown-headed
                cowbirds (Molothrus ater). Brown-headed cowbirds are obligate brood
                parasites. Females remove an egg from a host species' nest and lay
                their own egg to be raised by the adult hosts, usually resulting in the
                death of the remaining host nestlings (Rothstein 2004, p. 375). Prior
                to initiation of the brown-headed cowbird management program (discussed
                in more detail under Factor E: Brood Parasitism), Kirtland's warblers
                averaged less than one young fledged per nest (Walkinshaw 1983, p.
                151). After brown-headed cowbird control efforts began in 1972, the
                estimated number of chicks fledged per nest (1972 to 1977) increased to
                2.67, with 63.3 percent nest success (Walkinshaw 1983, pp. 150-152).
                More recently, mean annual reproductive success of 3.3 fledglings per
                year per male has been observed (Rockwell et al. 2012, p. 748).
                Genetics
                    From the information available, it appears that Kirtland's warblers
                display winter and breeding-ground panmixia (mixing of individuals
                across locations within the population). In 2007, eight birds examined
                from six different wintering sites on Eleuthera Island were found on
                breeding territories in the Damon KWMA in Ogemaw County, Michigan
                (Ewert, unpubl. data). Additionally, four other birds banded from one
                wintering site on Eleuthera Island were found on breeding territories
                across four counties in northern lower Michigan. Kirtland's warblers
                are also known to regularly move between KWMAs in northern lower
                Michigan during the breeding season (Probst et al. 2003, p. 371).
                Regardless of where they overwintered in The Bahamas (i.e., either Cat
                or Eleuthera Islands), Kirtland's warblers intermixed heavily on the
                breeding grounds and migrated to various sites throughout the breeding
                range, showing a weak connectivity between the breeding and wintering
                grounds (Cooper et al. 2018, pp. 5-6). These data suggest that the
                warbler's population exhibits panmictic (a group of interbreeding
                individuals where all individuals in the population are potential
                reproductive partners) rather than metapopulation (groups of
                interbreeding individuals that are geographically distinct) demographic
                characteristics (Esler 2000, p. 368).
                    Analysis of microsatellite DNA markers from Kirtland's warblers in
                Oscoda County, Michigan, over three time periods (1903-1912, 1929-1955,
                and 2008-2009) showed no evidence of a genetic bottleneck in the oldest
                (1903-1912) sample, indicating that any population declines prior to
                that point may have been gradual (Wilson et al. 2012, pp. 7-9).
                Although population declines have been observed since then, there was
                only weak genetic evidence of a bottleneck in the two more recent
                samples (no bottleneck detected in two of three possible models for
                each sample). The study showed a slight loss of allelic richness
                between the oldest and more recent samples, but no significant
                difference in heterozygosity between samples and no evidence of
                inbreeding. Effective population size estimates varied depending on the
                methods used, but none was low enough to indicate that inbreeding or
                rapid loss of genetic diversity were likely in the future (Wilson et
                al. 2012, pp. 7-9). Based on the available data, genetic diversity does
                not appear to be a limiting factor for the Kirtland's warbler or
                indicate the need for genetic management at this time.
                Abundance and Population Trends
                    Prior to 1951, the size of the Kirtland's warbler population was
                extrapolated from anecdotal observations and knowledge about breeding
                and wintering habitat conditions. The Kirtland's warbler population may
                have peaked in the late 1800s, a time when conditions across the
                species' distribution were universally beneficial (Mayfield 1960, p.
                32). Wildfires associated with intensive logging, agricultural burning,
                and railroads in the Great Lakes region burned hundreds of thousands of
                acres, and vast portions were dominated by jack pine forests (Pyne
                1982, pp. 199-200, 214). Suitable winter habitat consisting of low
                coppice (early-successional and dense, broadleaf vegetation) was also
                becoming more abundant, due to a decrease in widespread commercial
                agriculture in The Bahamas after the abolition of slavery in 1834,
                resulting in former croplands converting to scrub (low coppice) (Sykes
                and Clench 1998, p. 245). During this time, Kirtland's warblers were
                found in greater abundance throughout The Bahamas than were found in
                previous decades, and reports of migratory strays came from farther
                north and west of the known migratory range, evidence of a larger
                population that would produce more migratory strays (Mayfield 1993, p.
                352).
                    Between the early 1900s and the 1920s, agriculture in the northern
                Great Lakes forests was being discouraged in favor of industrial tree
                farming, and systematic fire suppression was integrated into State and
                Federal policy (Brown 1999, p. 9). The estimated amount of jack pine on
                the landscape suitably aged for Kirtland's warblers had decreased to
                approximately 40,470 ha (100,000 ac) of suitable habitat in any one
                year (Mayfield 1960, p. 26). This reduction in habitat presumably
                resulted in fewer Kirtland's warblers from the preceding time period,
                and Kirtland's warblers were not observed in all stands of suitable
                conditions (Wood 1904, p. 10). Serious efforts to control forest fires
                in Michigan began in 1927 and resulted in a further reduction of total
                acres burned as the number and size of wildfires decreased (Mayfield
                1960, p. 26; Radtke and Byelich 1963, p.
                [[Page 54441]]
                210). By this time, brown-headed cowbirds had expanded from the
                shortgrass plains and become common within the Kirtland's warbler's
                nesting range due to clearing of land for settlement and farming in
                northern Michigan (Wood and Frothingham 1905, p. 49; Mayfield 1960, p.
                146), further contributing to the decline of Kirtland's warblers.
                [GRAPHIC] [TIFF OMITTED] TR09OC19.025
                    Figure: Kirtland's warbler census results for each year in which a
                full census was completed (1951, 1961, 1971-2013, and 2015) (MDNR
                data). Note: A rangewide census was not conducted in the years 1952-
                1960, 1962-1970, 2014, or 2016-2018.
                    Comprehensive surveys (censuses) of the entire Kirtland's warbler
                population began in 1951. Because of the warbler's specific habitat
                requirements and the frequent, loud, and persistent singing of
                territorial males during the breeding season, it was possible to
                establish a singing male census (Ryel 1976, pp. 1-2). The census
                consists of an extensive annual survey of all known and potential
                breeding habitat to count singing males.
                    Censuses were conducted in 1951, 1961, each year from 1971 to 2013,
                and 2015 (see figure, above). The 1951 census documented a population
                of 432 singing males confined to 28 townships in eight counties in
                northern lower Michigan (Mayfield 1953, p. 18). By 1971, the Kirtland's
                warbler population declined to approximately 201 singing males and was
                restricted to just 16 townships in six counties in northern lower
                Michigan (Probst 1986, pp. 89-90). Over the next 18 years, the
                Kirtland's warbler population level remained relatively stable at
                approximately 200 singing males but experienced record lows of 167
                singing males in 1974 and again in 1987. In response to conservation
                efforts, including artificial regeneration of jack pine habitat (see
                Breeding Habitat, above) and brown-headed cowbird trapping program, the
                population of Kirtland's warbler began to increase dramatically
                starting in the 1990s (see figure, above) and occupy a wider
                distribution across the landscape. The population reached a record high
                of 2,383 singing males in 2015, the year of the last full census (MDNR,
                USFS, USFWS, unpubl. data).
                    The census protocol counts singing males, not breeding pairs. Since
                the census began, Kirtland's warbler conservation partners have often
                made the assumption that there is a breeding female for each singing
                male, so the number of singing males has often been used to approximate
                the number of breeding pairs. Likewise, some reports estimate a total
                breeding population by doubling the number of singing males.
                Extrapolating from singing males to breeding pairs or total breeding
                population should be done with caution. Mating success of males may
                vary depending on the quality of habitat, method of regeneration, or
                other factors (Bocetti 1994, pp. 80-85; Rockwell et al. 2013, p. 748;
                Bocetti 2018, pers. comm.). The annual census provides a robust,
                relative index of the Kirtland's warbler population change over time,
                but results should not be interpreted as an absolute count (Probst et
                al. 2005, pp. 50-59).
                Population Viability
                    Full annual cycle (breeding and wintering) dynamics were
                incorporated into a population viability model to assess the long-term
                population viability of the Kirtland's warbler under five management
                scenarios: (1) Current suitable habitat and current brown-
                [[Page 54442]]
                headed cowbird removal; (2) reduced suitable habitat and current brown-
                headed cowbird removal; (3) current suitable habitat and reduced brown-
                headed cowbird removal, (4) current suitable habitat and no brown-
                headed cowbird removal; and (5) reduced suitable habitat and reduced
                brown-headed cowbird removal (Brown et al. 2017a, p. 443). The model
                that best simulated recently observed Kirtland's warbler population
                dynamics included a relationship between precipitation in the species'
                wintering grounds and productivity (Brown et al. 2017a, pp. 442, 444),
                which reflects our understanding of carry-over effects (Rockwell et al.
                2012, pp. 748-750; Wunderle et al. 2014, pp. 46-48).
                    Under the current management conditions scenario, which includes
                habitat management at existing levels and brown-headed cowbird control
                occurring throughout the northern Lower Peninsula of Michigan, the
                model predicts that the Kirtland's warbler population will be stable
                over a 50-year simulation period. When simulating a reduced brown-
                headed cowbird removal effort by restricting cowbird trapping
                activities to the central breeding areas in northern lower Michigan
                (i.e., eastern Crawford County, southeastern Otsego County, Oscoda
                County, western Alcona County, Ogemaw County, and Roscommon County) and
                assuming a 41 percent or 57 percent reduction in Kirtland's warbler
                productivity, the results showed a stable or slightly declining
                population, respectively, over the 50-year simulation period (Brown et
                al. 2017a, p. 447). Other scenarios, including reduced habitat
                suitability and reduced Kirtland's warbler productivity due to
                experimental jack pine management on 25 percent of available breeding
                habitat, had similar results with projected population declines over
                the 50-year simulation period, but mean population numbers remained
                above the population goal of 1,000 pairs (Brown et al. 2017a, p. 446),
                the numerical criterion identified in the Kirtland's warbler recovery
                plan (USFWS 1985).
                    Future reductions to Kirtland's warbler productivity rates under
                two reduced cowbird removal scenarios were assumed to be similar to
                historical rates (Brown et al. 2017a, p. 447). This assumption would
                overestimate the negative effects on Kirtland's warbler productivity if
                future parasitism rates are lower than the rates modeled (see Factor E:
                Brood Parasitism, below, for additional information on contemporary
                parasitism rates). Supplementary analysis (Brown et al. 2017b, unpubl.
                report), using the model structure and assumptions of Brown et al.
                (2017a), simulated the impacts of a 5, 10, 20, and 30 percent reduction
                in productivity to take into consideration a wider range of possible
                future parasitism rates. Even small reductions in annual productivity
                had measurable impacts on population abundance, but there were not
                substantial differences in mean population growth rate up to a 20
                percent reduction in productivity (Brown et al. 2017b, p. 3). Even with
                annual reductions in productivity of up to 5 percent for 50 years, the
                population trend (growth rate) projected for the final 30 years of the
                model simulations was 0.998 (range from the 5 simulations 0.993 to
                1.007) or nearly the same as that projected in the simulations with no
                reduction in productivity at 0.999 (range of 0.995 to 1.008) (Brown et
                al. 2017b, p. 3). It is reasonable to infer that the Kirtland's warbler
                population can support relatively small reductions in productivity over
                a long period of time (e.g., the 50-year timeframe of the simulations),
                providing a margin of assurance as management approaches are adaptively
                managed over time, and the species may be able to withstand as much as
                a 20 percent reduction in annual productivity, provided it does not
                extend over several years.
                    The results of the model simulations are more helpful in evaluating
                the effect of various management decisions relative to one another,
                rather than providing predictions of true population abundance. In
                other words, the model output provides projections of relative trends,
                rather than identifying specific population abundance thresholds.
                Although there are limitations to all population models based on
                necessary assumptions, input data limitations, and unknown long-term
                responses such as adaptation and plasticity, data simulated by Brown et
                al. (2017a and 2017b, entire) provide useful information in assessing
                relative population trends for the Kirtland's warbler under a variety
                of future scenarios and provide the best available analysis of
                population viability.
                    In summary, Kirtland's warbler population numbers have been greatly
                affected by brown-headed cowbird parasitism rates and the extent and
                quality of available habitat on the breeding grounds. The best
                available population model predicts that limited non-traditional
                habitat management and continued low brood parasitism rates will result
                in sustained population numbers above the recovery goal. Monitoring
                population numbers and brood parasitism rates will be important in
                ensuring the Kirtland's warbler population remains stable post-
                delisting (see Post-delisting Monitoring, below).
                Recovery and Recovery Plan Implementation
                    State and Federal efforts to conserve the Kirtland's warbler began
                in 1957 and were focused on providing breeding habitat for the species.
                The Kirtland's warbler was federally listed as an endangered species in
                1967, under the Endangered Species Preservation Act of 1966 (Pub. L.
                89-669). By 1972, a Kirtland's Warbler Advisory Committee formed to
                coordinate management efforts and research actions across Federal and
                State agencies, and conservation efforts expanded to include management
                of brown-headed cowbird brood parasitism (Shake and Mattsson 1975, p.
                2).
                    Efforts to protect and conserve the Kirtland's warbler were further
                enhanced when the Endangered Species Act of 1973 became law and
                provided for acquisition of land to increase available habitat, funding
                to carry out additional management programs, and provisions for State
                and Federal cooperation. In 1975, the Recovery Team was appointed by
                the Secretary of the Interior to guide recovery efforts. A Kirtland's
                Warbler Recovery Plan was completed in 1976 (USFWS 1976), and updated
                in 1985 (USFWS 1985), outlining steps designed to protect and increase
                the species' population.
                    Recovery plans provide important guidance to the Service, States,
                and other partners on methods of minimizing threats to listed species
                and measurable objectives against which to measure progress towards
                recovery, but they are not regulatory documents. A decision to revise
                the status of or remove a species from the List is ultimately based on
                an analysis of the best scientific and commercial data available to
                determine whether a species is no longer an endangered species or a
                threatened species, regardless of whether that information differs from
                the recovery plan.
                    The Kirtland's warbler recovery plan (USFWS 1985) identifies one
                ``primary objective'' (hereafter referred to as ``recovery criterion'')
                that identifies when the species should be considered for removal from
                the List, and ``secondary objectives'' (hereafter referred to as
                ``recovery actions'') that are designed to accomplish the recovery
                criterion. The recovery criterion states that the Kirtland's warbler
                may be considered recovered and considered for removal from the List
                when a self-sustaining population has been re-established throughout
                its known range at a minimum level of 1,000 pairs. The
                [[Page 54443]]
                1,000-pair goal was informed by estimates of the amount of the specific
                breeding habitat required by each breeding pair of Kirtland's warblers,
                the amount of potential habitat available on public lands in Michigan's
                northern Lower Peninsula, and the ability of State and Federal land
                managers to provide suitable nesting habitat on an annual basis. The
                recovery criterion was intended to address the point at which the
                ultimate limiting factors to the species had been ameliorated so that
                the population is no longer in danger of extinction or likely to become
                so within the foreseeable future.
                    The recovery plan does not clearly articulate how meeting the
                recovery criterion will result in a population that is at reduced risk
                of extinction. The primary threats to the Kirtland's warbler are
                pervasive and recurring threats, but threat-based criteria specifying
                measurable targets for control or reduction of those threats were not
                incorporated into the recovery plan. Instead, the recovery plan focused
                on specific actions necessary to accomplish the recovery criterion.
                These included managing breeding habitat, protecting the Kirtland's
                warbler on its wintering grounds and along the migration route,
                reducing key factors such as brown-headed cowbird parasitism from
                adversely affecting reproduction and survival of Kirtland's warblers,
                and monitoring the Kirtland's warbler to evaluate responses to
                management practices and environmental changes.
                    At the time the recovery plan was prepared, we estimated that land
                managers would need to annually maintain approximately 15,380 ha
                (38,000 ac) of nesting habitat in order to support and sustain a
                breeding population of 1,000 pairs (USFWS 1985, pp. 18-20). We
                projected that this would be accomplished by protecting existing
                habitat, improving occupied and developing habitat, and establishing
                approximately 1,010 ha (2,550 ac) of new habitat each year, across
                51,640 ha (127,600 ac) of State and Federal pine lands in the northern
                Lower Peninsula of Michigan (USFWS 1985, pp. 18-20). We also
                prioritized development and improvement of guidelines that would
                maximize the effectiveness and cost efficiency of habitat management
                efforts (USFWS 1985, p. 24). The MDNR, USFS, and Service developed the
                Strategy for Kirtland's Warbler Habitat Management (Huber et al. 2001,
                entire) to update Kirtland's warbler breeding habitat management
                guidelines and prescriptions based on a review of past management
                practices, analysis of current habitat conditions, and new findings
                that would continue to conserve and enhance the status of the
                Kirtland's warbler (Huber et al. 2001, p. 2).
                    By the time the recovery plan was updated in 1985, the brown-headed
                cowbird control program had been in effect for more than 10 years. The
                brown-headed cowbird control program had virtually eliminated brood
                parasitism and more than doubled the warbler's productivity rates in
                terms of fledging success (Shake and Mattsson 1975, pp. 2-4). The
                Kirtland's warbler's reproductive capability had been successfully
                restored, and the brown-headed cowbird control program was credited
                with preventing further decline of the species. Because management of
                brown-headed cowbird brood parasitism was considered essential to the
                survival of the Kirtland's warbler, it was recommended that the brown-
                headed cowbird control program be maintained for ``as long as
                necessary'' (USFWS 1985, p. 27).
                    Although the recovery plan identifies breeding habitat as the
                primary limiting factor, with brood parasitism as a secondary limiting
                factor, it also suggests that events or factors outside the breeding
                season might be adversely affecting survival (USFWS 1985, pp. 12-13).
                At the time the recovery plan was updated, little was known about the
                Kirtland's warbler's migratory and wintering behavior, the species'
                migratory and wintering habitat requirements, or ecological changes
                that may have occurred within the species' migration route or on its
                wintering range. This lack of knowledge emphasized a need for more
                information on the Kirtland's warbler post-fledging, during migration,
                and on its wintering grounds (Kelly and DeCapita 1982, p. 365).
                Accordingly, recovery efforts were identified to: (1) Define the
                migration route and locate wintering areas; (2) investigate the ecology
                of the Kirtland's warbler and factors that might be affecting mortality
                during migration and on its winter range; and (3) provide adequate
                habitat and protect the Kirtland's warbler during migration and on its
                wintering areas (USFWS 1985, pp. 24-26).
                    In correspondence with the Service's Midwest Regional Director, and
                based on more than 20 years of research on the Kirtland's warbler's
                ecology and response to recovery efforts, the Recovery Team helped
                clarify recovery progress and issues that needed attention prior to
                reclassification to threatened status or delisting (Ennis 2002, pp. 1-
                4; Ennis 2005, pp. 1-3). From that synthesis, several important
                concepts emerged that continued to inform recovery, including: (1)
                Breeding habitat requirements, amount, configuration, and distribution;
                (2) brood parasitism management; (3) migratory connectivity and
                protection of Kirtland's warblers and their habitat during migration
                and on the wintering grounds; and (4) establishment of credible
                mechanisms to ensure the continuation of necessary management (Thorson
                2005, pp. 1-2).
                    Our understanding of the Kirtland's warbler's breeding habitat
                selection and use, and the links between maintaining adequate amounts
                of breeding habitat and a healthy Kirtland's warbler population, has
                continued to improve. As the population has rebounded, Kirtland's
                warblers have become reliant on artificial regeneration of breeding
                habitat, but have also recolonized naturally regenerated areas within
                the historical range of the species and nested in habitat types
                previously considered non-traditional or less suitable. As explained in
                more detail below, recovery efforts have expanded to establish and
                enhance management efforts on the periphery of the species' current
                breeding range in Michigan's Upper Peninsula, Wisconsin, and Canada and
                reflect the best scientific understanding of the amount and
                configuration of breeding habitat (see Factor A discussion, below).
                These adjustments improve the species' ability to adapt to changing
                environmental conditions and to withstand stochastic disturbance and
                catastrophic events, and better ensure long-term conservation for the
                species.
                    Along with habitat management, brown-headed cowbird control has
                proven to be a very effective tool in stabilizing and increasing the
                Kirtland's warbler population. To ensure survival of the Kirtland's
                warbler, we anticipate that continued brown-headed cowbird brood
                parasitism management may be needed, at varying levels depending on
                parasitism rates, to sustain adequate Kirtland's warbler productivity.
                As explained in more detail below, brown-headed cowbird control
                techniques and the scale of trapping efforts have adapted over time and
                will likely continue to do so, in order to maximize program
                effectiveness and feasibility (see Factor E: Brood Parasitism
                discussion, below).
                    We now recognize that the Kirtland's warbler persists only through
                continual management activities designed to mitigate recurrent threats
                to the species. The Kirtland's warbler is considered a conservation-
                reliant species, which means that it requires continuing management to
                address ongoing threats (Goble et al. 2012, p. 869). Conservation of
                the Kirtland's warbler will continue
                [[Page 54444]]
                to require a coordinated, multi-agency approach for planning and
                implementing conservation efforts into the future. Four elements that
                should be in place prior to delisting a conservation-reliant species
                include a conservation partnership capable of continued management, a
                conservation plan, appropriate binding agreements (such as memoranda of
                agreement (MOAs)) in place, and sufficient funding to continue
                conservation actions into the future (Bocetti et al. 2012, p. 875).
                    The Kirtland's warbler has a strong conservation partnership
                consisting of multiple stakeholders that have invested considerable
                time and resources to achieving and maintaining this species' recovery.
                Since 2016, the Recovery Team is no longer active, but instead new
                collaborative efforts formed to help ensure the long-term conservation
                of the Kirtland's warbler regardless of its status under the ESA. These
                efforts formed to facilitate conservation planning through
                coordination, implementation, monitoring, and research efforts among
                many partners and across the species' range. A coalition of
                conservation partners lead by Huron Pines, a nonprofit conservation
                organization based in northern Michigan, launched the Kirtland's
                Warbler Initiative in 2013. The Kirtland's Warbler Initiative brings
                together State, Federal, and local stakeholders to identify and
                implement strategies to secure funds for long-term Kirtland's warbler
                conservation actions given the continuous, recurring costs anticipated
                with conserving the species into the future. The goal of this
                partnership is to ensure the Kirtland's warbler thrives and ultimately
                is delisted, as a result of strong public-private funding and land
                management partnerships. Through the Kirtland's Warbler Initiative, a
                stakeholder group called the Kirtland's Warbler Alliance was developed
                to raise awareness in support of the Kirtland's warbler and the
                conservation programs necessary for the health of the species and jack
                pine forests.
                    The second effort informing Kirtland's warbler conservation efforts
                is the Kirtland's Warbler Conservation Team (KWCT). The KWCT was
                established to preserve institutional knowledge, share information, and
                facilitate communication and collaboration among agencies and partners
                to maintain and improve Kirtland's warbler conservation. The current
                KWCT is comprised of representatives from the Service, USFS, MDNR,
                WDNR, U.S. Department of Agriculture's Wildlife Services (USDA-WS),
                Canadian Wildlife Service, Huron Pines, Kirtland's Warbler Alliance,
                The Nature Conservancy, and California University of Pennsylvania.
                    Since 2015, conservation efforts for the Kirtland's warbler have
                been guided by the Kirtland's Warbler Breeding Range Conservation Plan
                (Conservation Plan) (MDNR et al. 2015, entire). The Conservation Plan
                outlines the strategy for future cooperative Kirtland's warbler
                conservation and provides technical guidance to land managers and
                others on how to create and maintain Kirtland's warbler breeding
                habitat within an ecosystem management framework. The scope of the
                Conservation Plan currently focuses only on the breeding range of the
                Kirtland's warbler within the United States, although the agencies
                involved (MDNR, USFS, and USFWS; hereafter ``agencies'' or ``management
                agencies'') intend to cooperate with other partners to expand the scope
                of the plan in the future to address the entire species' range (i.e.,
                the entire jack pine ecosystem, as well as the migratory route and
                wintering range of the species). The Conservation Plan will be revised
                every 10 years to incorporate any new information and the best
                available science (MDNR et al. 2015, p. 1).
                    In April 2016, the management agencies renewed a memorandum of
                understanding (MOU) through December 31, 2020, committing to continue
                collaborative habitat management, brown-headed cowbird control,
                monitoring, research, and education in order to maintain the Kirtland's
                warbler population at or above 1,000 breeding pairs, regardless of the
                species' legal protection under the ESA (USFWS, MDNR, and USFS 2016,
                entire). In addition, Kirtland's warbler conservation actions are
                included in the USFS's Land and Resource Management Plans (Forest
                Plans), which guide management priorities for the Huron-Manistee,
                Hiawatha, and Ottawa National Forests.
                    Funding mechanisms that support long-term land management and
                brown-headed cowbird control objectives are in place to assure a high
                level of certainty that the agencies can meet their commitments to the
                conservation of the Kirtland's warbler. MDNR and USFS have replanted
                approximately 26,420 ha (90,000 ac) of Kirtland's warbler habitat over
                the past 30 years. Over the last 10 years, only a small proportion of
                the funding used to create Kirtland's warbler habitat is directly tied
                to the ESA through the use of grant funding (i.e., funding provided to
                MDNR through the Service's section 6 grants to States' program).
                Although there is the potential that delisting could reduce the
                priority for Kirtland's warbler work within MDNR and USFS, as noted in
                the Conservation Plan (MDNR 2015, p. 17), much of the forest management
                cost (e.g., silvicultural examinations, sale preparation, and
                reforestation) is not specific to maintaining Kirtland's warbler
                breeding habitat and would likely be incurred in the absence of the
                Kirtland's warbler. MDNR and USFS have successfully navigated budget
                shortfalls and changes in funding sources over the past 30 years and
                were able to provide sufficient breeding habitat to enable the
                population to recover, and they have agreed to continue to do so
                through the MOU. Additionally, the Service and MDNR developed an MOA to
                set up a process for managing funds to help address long-term
                conservation needs, specifically brown-headed cowbird control (USFWS
                and MDNR 2015). If the annual income generated is greater than the
                amount needed to manage brown-headed cowbird parasitism rates, the
                remaining portion of the annual income may be used to support other
                high priority management actions to directly benefit the Kirtland's
                warbler, including wildlife and habitat management, land acquisition
                and consolidation, and education. The MOA requires that for a minimum
                of 5 years after the species is delisted, MDNR consult with the Service
                on planning the annual brown-headed cowbird control program and other
                high-priority actions. In addition, MDNR recently reaffirmed their
                commitment to the MOA and confirmed their intent to implement and
                administer the brown-headed cowbird control program, even if the
                Kirtland's warbler is delisted (MDNR 2017).
                    In summary, the general guidance of the recovery plan has been
                effective, and the Kirtland's warbler has responded well to active
                management over the past 50 years. The primary threats identified at
                listing and during the development of the recovery plan have been
                managed, and commitments are in place to continue managing the threats.
                The status of the Kirtland's warbler has improved, primarily due to
                breeding habitat and brood parasitism management provided by MDNR,
                USFS, and the Service. The population has been above the 1,000 pair
                goal since 2001, above 1,500 pairs since 2007, and above 2,000 pairs
                since 2012. The recovery criterion has been met. Since 2015, efforts
                for the Kirtland's warbler have been guided by a Conservation Plan that
                will continue to be implemented by the management agencies when the
                species is delisted.
                [[Page 54445]]
                    Since the revision of the recovery plan (USFWS 1985), decades of
                research have been invaluable to refining recovery implementation and
                have helped clarify our understanding of the dynamic condition of the
                Kirtland's warbler, jack pine ecosystem, and factors influencing them.
                The success of recovery efforts in mitigating threats to the Kirtland's
                warbler are evaluated below.
                Summary of Changes From the Proposed Rule
                    Based upon our review of the comments received on the April 12,
                2018, proposed rule (83 FR 15758), peer review comments, and new
                information that became available since the publication of the proposed
                rule, we reevaluated the information in the proposed rule and made
                changes as appropriate. We made the following changes in this final
                rule: (1) We added detail on the wintering distribution; (2) we
                clarified that wintering habitat is broadleaf scrub rather than pine
                habitat; (3) we added a paragraph on reproductive success; (4) we added
                a discussion on anthropogenic disturbance regimes on the wintering
                grounds; (5) we added information on connectivity between winter and
                breeding grounds; (6) we clarified that census results (number of
                singing males) are a relative index rather than an absolute count; (7)
                we added a section on the effects of insects and disease to jack pine;
                (8) we added a discussion of the effects of recreation; (9) we added a
                discussion of pesticides; (10) we included new data on brown-headed
                cowbird parasitism rates and the suspended trapping program during
                2018; (11) we updated the analysis on effects of climate change on
                breeding grounds; (12) we added a discussion of recent drought on the
                wintering grounds; (13) we included new data on risk of heavy rainfall
                events and extended period of hurricane force winds due to decreasing
                translational speeds; and (14) we added a discussion of the effects of
                hurricanes. In addition, we made efforts to improve clarity, improve
                organization, and correct typographical or other minor errors. Many of
                our edits were based on comments from peer reviewers and public
                comments; additional detail can be found under Summary of Comments and
                Recommendations, below.
                Summary of Factors Affecting the Kirtland's Warbler
                    Section 4 of the ESA and its implementing regulations (50 CFR part
                424) set forth the procedures for listing species, reclassifying
                species, or removing species from listed status. The term ``species''
                includes ``any subspecies of fish or wildlife or plants, and any
                distinct population segment [DPS] of any species of vertebrate fish or
                wildlife which interbreeds when mature'' (16 U.S.C. 1532(16)). A
                species may be determined to be an endangered species or threatened
                species because of any one or a combination of the five factors
                described in section 4(a)(1) of the ESA: (A) The present or threatened
                destruction, modification, or curtailment of its habitat or range; (B)
                overutilization for commercial, recreational, scientific, or
                educational purposes; (C) disease or predation; (D) the inadequacy of
                existing regulatory mechanisms; or (E) other natural or manmade factors
                affecting its continued existence. We must consider these same five
                factors in delisting a species. We may delist a species according to 50
                CFR 424.11(d) if the best available scientific and commercial data
                indicate that the species is neither endangered nor threatened for one
                or more of the following reasons: (1) The species is extinct; (2) the
                species has recovered and is no longer endangered or threatened; or (3)
                the original scientific data used at the time the species was
                classified were in error.
                    For species that are already listed as endangered or threatened,
                this analysis of threats is an evaluation of both the threats currently
                facing the species and the threats that are reasonably likely to affect
                the species in the foreseeable future following delisting or
                downlisting (i.e., reclassification from endangered to threatened) and
                the removal or reduction of the ESA's protections. A recovered species
                is one that no longer meets the ESA's definition of endangered or
                threatened. A species is ``endangered'' for purposes of the ESA if it
                is in danger of extinction throughout all or a ``significant portion of
                its range'' and is ``threatened'' if it is likely to become endangered
                within the foreseeable future throughout all or a ``significant portion
                of its range.'' The word ``range'' in the ``significant portion of its
                range'' phrase refers to the range in which the species currently
                exists. For the purposes of this analysis, we will evaluate whether the
                Kirtland's warbler should be considered endangered or threatened
                throughout all of its range. Then we will consider whether there are
                any significant portions of the Kirtland's warbler's range where the
                species is in danger of extinction or likely to become so within the
                foreseeable future.
                    The ESA does not define the term ``foreseeable future.'' For the
                purpose of this rule, we define the ``foreseeable future'' to be the
                extent to which, given the amount and substance of available data, we
                can anticipate events or effects, or reliably extrapolate threat
                trends, such that we reasonably believe that reliable predictions can
                be made concerning the future as it relates to the status of the
                Kirtland's warbler. We used the anticipated habitat and brown-headed
                cowbird management analyzed over a 50-year timeframe in Brown et al.
                (2017a, b) to define the foreseeable future for the Kirtland's warbler.
                This analysis considered multiple future management scenarios for
                Kirtland's warbler, including reduced suitable habitat (from
                experimental habitat management) and reduced brown-headed cowbird
                removal. Given the length of time for habitat to become suitable and
                the warbler's average life span, a 50-year period takes into account
                multiple rotations of habitat and generations of birds. This is a
                sufficient amount of time to fully evaluate if the current and
                potential future experimental approaches to management warrant further
                refinement. Beyond 50 years, the future conditions become more
                uncertain, such that we cannot make reliable predictions as to how any
                differing management scenarios may affect the status of the species.
                    In considering what factors might constitute threats, we must look
                beyond the exposure of the species to a particular factor to evaluate
                whether the species may respond to the factor in a way that causes
                actual impacts to the species. If there is exposure to a factor and the
                species responds negatively, the factor may be a threat, and during the
                status review, we attempt to determine how significant a threat it is.
                The threat is significant if it drives or contributes to the risk of
                extinction of the species, such that the species warrants listing as
                endangered or threatened as those terms are defined by the ESA.
                However, the identification of factors that could impact a species
                negatively may not be sufficient to compel a finding that the species
                warrants listing. The information must include evidence sufficient to
                suggest that the potential threat is likely to materialize and that it
                has the capacity (i.e., it should be of sufficient magnitude and
                extent) to affect the species' status such that it meets the definition
                of endangered or threatened under the ESA. The following analysis
                examines all five factors currently affecting or that are likely to
                affect the Kirtland's warbler in the foreseeable future.
                [[Page 54446]]
                A. The Present or Threatened Destruction, Modification, or Curtailment
                of Its Habitat or Range
                Breeding Habitat
                    Historically, wildfires were the most important factor in the
                establishment of natural jack pine forests and Kirtland's warbler
                breeding habitat. However, modern wildfire suppression greatly altered
                the natural disturbance regime that generated Kirtland's warbler
                breeding habitat for thousands of years (USFWS 1985, p. 12; Cleland et
                al. 2004, pp. 316-318). Prior to the 20th century, the historic fire
                recurrence in jack pine forests averaged 59 years, but it is now
                estimated to occur in cycles as long as 775 years (Cleland et al. 2004,
                pp. 315-316).
                    In the absence of wildfire, land managers must take an active role
                in mimicking natural processes that regularly occurred within the jack
                pine ecosystem, namely stand-replacing disturbance events. This is
                primarily done through large-scale timber harvesting and human-assisted
                reforestation. Although planted stands tend to be more structurally
                simplified than wildfire-regenerated stands (Spaulding and Rothstein
                2009, p. 2610), land managers have succeeded in selecting KWMAs that
                have landscape features of the natural breeding habitat and have
                developed silvicultural techniques that produce conditions within
                planted stands suitable for Kirtland's warbler nesting. In fact, over
                85 percent of the habitat used by breeding Kirtland's warblers in 2015
                in the northern Lower Peninsula of Michigan (approximately 12,343 ha
                (30,500 ac)) had been artificially created through clearcut harvest and
                replanting. The planted stands supported over 92 percent of the
                warbler's population within the Lower Peninsula during the 2015
                breeding season (MDNR, USFS, USFWS, unpubl. data). The effectiveness of
                these strategies is also evident by the reproductive output observed in
                planted stands, which function as population sources (Bocetti 1994, p.
                95). Thus, in a landscape where natural fire disturbance patterns have
                been reduced, threats to natural breeding habitat are being mitigated
                through large-scale habitat management. Therefore, the status of the
                Kirtland's warbler depends largely on the continued production of
                managed breeding habitat.
                    Federal and State laws establish the foundation for managing the
                USFS, USFWS, and MDNR lands that provide the majority of the breeding
                habitat for Kirtland's warbler. These laws require land management
                agencies to develop plans that describe objectives and goals for forest
                management.
                    The National Forest Management Act (16 U.S.C. 1600-1640; NFMA)
                requires that Forest Plans shall ``provide for multiple use and
                sustained yield of the products and services . . . and, in particular,
                include coordination of outdoor recreation, range, timber, watershed,
                wildlife and fish, and wilderness'' (16 U.S.C. 1604(e)). All projects
                and activities authorized by the Forest Service must be consistent with
                the established Forest Plans (16 U.S.C. 1604(i)). The Hiawatha, Huron-
                Manistee, and Ottawa National Forest Plans include specific goals and
                objectives for maintaining Kirtland's warbler breeding habitat (USFS
                2006a, p. 35; USFS 2006b, p. 82; USFS 2006c, p. 27). The NFMA's
                implementing regulations will apply to any future Forest Plan revisions
                and currently require National Forests to develop plans that include
                standards or guidelines to maintain or restore the ecological integrity
                of terrestrial ecosystems in the plan area (36 CFR 219.8(a)). Further,
                additional species-specific standards or guidelines may be required to
                maintain a viable population of each species of conservation concern
                within the plan area (36 CFR 219.9(b)(1)). The Forest Service plans to
                designate Kirtland's warbler as a Sensitive Species upon delisting for
                a period of at least five years (Hogeboom 2019, pers. comm.).
                Additionally, in accordance with the Forest Service Manual (FSM), any
                significant current or predicted downward trends in population numbers,
                density, or in habitat capability that would reduce a species' existing
                distribution would be triggers for the Regional Forester to designate
                the Kirtland's warbler as a Sensitive Species (FSM 2670.5) in the
                future. Forest Service objectives for Sensitive Species (FSM 2670.22)
                include developing and implementing management practices to ensure that
                species do not become threatened or endangered because of Forest
                Service actions.
                    The National Wildlife Refuge System Improvement Act of 1997
                requires the preparation of Comprehensive Conservation Plans for refuge
                lands and maintenance of the biological integrity, diversity, and
                environmental health of the National Wildlife Refuge System. The
                Service's Kirtland's Warbler Wildlife Management Area defines goals,
                objectives, and strategies that support Kirtland's warbler and the jack
                pine ecosystem (USFWS 2009, pp. 31-33).
                    In Michigan law, Part 525, Sustainable Forestry on State Forest
                Lands, of the Natural Resources and Environmental Protection Act (1994
                PA 451, as amended) requires the MDNR to manage the State forest lands
                consistent with the principles of sustainable forestry. Part 525 also
                requires the MDNR to maintain third-party certification of the
                management of the State forest that satisfies sustainable forestry
                standards. The MDNR forest lands are certified under the standards of
                the Forest Stewardship Council and the Sustainable Forestry Initiative
                (Kintigh 2019, pers. comm.). These standards also require the MDNR to
                write, implement, and maintain forest management plans. The MDNR has
                developed a Regional State Forest Management Plan for the northern
                Lower Peninsula ecoregion that includes specific plans for 15 units of
                land managed for Kirtland's warbler (MDNR 2013, pp. 337-354). The
                Federal and State forest management planning standards, which will
                remain in effect after delisting, are synthesized and further refined
                for Kirtland's warbler through the Conservation Plan (MDNR et al.
                2015).
                    The Conservation Plan (MDNR et al. 2015) identifies continued
                habitat management needs and objectives to maintain sufficient suitable
                breeding habitat for Kirtland's warblers. Habitat management is
                currently conducted on approximately 88,626 ha (219,000 ac) of jack
                pine forest within MDNR, USFS, and Service lands throughout the
                northern Lower Peninsula and Upper Peninsula of Michigan (MDNR et al.
                2015, pp. 22-23). The Conservation Plan incorporates some conservative
                assumptions about the area needed to support a breeding pair of
                Kirtland's warblers, as well as how long a stand will be used by the
                species. The density and duration of use estimates were developed by
                data gathered over the last decade. Lands within the Lower Peninsula
                averaged 8 to 9 ha (19 to 22 ac) per pair and had a duration of use
                between 9 and 10 years. Lands within the Upper Peninsula on the
                Hiawatha National Forest required an average of 40 ha (100 ac) per pair
                and had a duration of use averaging 10 years (Huber et al. 2013, cited
                in MDNR et al. 2015, p. 22). Using those measures of average hectares
                per pair and duration of use, 14,593 ha (36,060 ac) of suitable
                breeding habitat would need to be available at all times to maintain a
                minimum population of 1,300 pairs, requiring land management agencies
                to jointly manage 1,550 ha (3,830 ac) of habitat annually (631 ha
                (1,560 ac) on MDNR land and 918 ha (2,270 ac) on USFS land) through
                wildfire-
                [[Page 54447]]
                regenerated jack pine or managed reforestation (MDNR et al. 2015, pp.
                22-23). Importantly, the more recent observations concerning density of
                Kirtland's warblers in breeding habitat and duration of stand use are
                often greater than the assumptions used for planning purposes and
                explain why the Kirtland's warbler population that is actually observed
                is higher than would be predicted based on the planning assumptions.
                    As described previously, the majority of managed breeding habitat
                is currently created through clear cutting and planting jack pine
                seedlings. However, managing jack pine for Kirtland's warbler breeding
                habitat typically results in lower value timber products due to the
                overall poor site quality in combination with the required spacing,
                density, and rotation age of the plantings (Greco 2017, pers. comm.).
                Furthermore, the demand for jack pine products has fluctuated in recent
                years, and long-term forecasts for future marketability of jack pine
                are uncertain. Commercially selling jack pine timber on sites where
                reforestation will occur is critical to the habitat management program.
                Timber receipts offset the cost of replanting jack pine at the
                appropriate locations, scales, arrangements, and densities needed to
                support a viable population of nesting Kirtland's warblers that would
                not otherwise be feasible through conservation dollars. The
                Conservation Plan directs management agencies to develop at least 75
                percent of the Kirtland's warbler's breeding habitat annual acreage
                objectives using traditional habitat management techniques (i.e.,
                opposing wave planting with interspersed openings), and no more than 25
                percent of annual acreage objectives should use non-traditional habitat
                management techniques (e.g., reduced stocking density, incorporating a
                red pine component within a jack pine stand, prescribed burning) (MDNR
                et al. 2015, p. 23). Using non-traditional techniques on a maximum of
                25 percent of breeding habitat acreage annually will allow the
                management agencies to evaluate new planting methods that improve
                timber marketability, reduce costs, and improve recreational
                opportunities while sustaining the warbler's population above the
                recovery criterion of 1,000 pairs. The KWCT is currently working on
                developing additional habitat regeneration techniques through adaptive
                management that increase the marketability of the timber at harvest
                while not substantially reducing Kirtland's warbler habitat suitability
                (Kennedy 2017, pers. comm.).
                    The land management agencies have maintained adequate breeding
                habitat despite times when their budgets were flat or declining, even
                while costs related to reforestation continued to increase. For
                example, over the last 30 years, MDNR replanted more than 20,000 ha
                (50,000 ac) of Kirtland's warbler habitat, averaging over 680 ha (1,700
                ac) per year. They took this action voluntarily, and within the past 10
                years, they used funding from sources in addition to those available
                under the ESA. Section 6 grants under the ESA have helped support
                MDNR's Kirtland's warbler efforts, but that funding has largely been
                used for population census work in recent years and reflects only a
                small percentage of the funding the State of Michigan spends annually
                to produce Kirtland's warbler breeding habitat. Other funding sources
                used by MDNR include State wildlife grants, competitive State wildlife
                grants, Michigan's Nongame Fund, and the Forest Development Fund.
                    Shifting agency priorities and competition for limited resources
                have and will continue to challenge the ability of land managers to
                fund reforestation of areas suitable for Kirtland's warblers. Low jack
                pine timber sale revenues, in conjunction with reduced budgets,
                increased Kirtland's warbler habitat reforestation costs, and
                competition with other programs, are all challenges that the land
                management agencies have met in the past and will need to continue
                addressing to meet annual habitat development objectives. Commitments
                by land managers and the KWCT are in place, as described earlier in
                this document, to ensure recovery of the Kirtland's warbler will be
                sustained despite these challenges.
                    The management agencies have agreed through the Conservation Plan
                (MDNR et al. 2015, pp. 24, 43-44) to generally limit or prohibit
                commercial, recreational, or infrastructure (e.g., roads, pipelines,
                communication towers) development within or near areas managed for
                Kirtland's warbler to protect them and provide for the long-term
                integrity of breeding habitat. Additionally, a regulatory mechanism
                that aids in the management of breeding habitat is Executive Order
                (E.O.) 13186, ``Responsibilities of Federal Agencies to Protect
                Migratory Birds'' (66 FR 3853; January 17, 2001), which directs Federal
                agencies to develop a memorandum of understanding (MOU) with the
                Service to promote the conservation of migratory bird populations. USFS
                and the Service signed an MOU (FS Agreement #08-MU-1113-2400-264),
                pursuant to E.O. 13186, with the purpose of strengthening migratory
                bird conservation by identifying and implementing strategies that
                promote conservation and avoid or minimize adverse impacts on migratory
                birds through enhanced collaboration.
                    Once planted for Kirtland's warbler habitat, jack pine trees need
                to survive to provide usable habitat. Multiple natural events, such as
                fire, drought, disease, and insect outbreaks, may affect the survival
                of jack pine trees and longevity of suitable habitat. Wildfire can be
                harmful to Kirtland's warblers when it destroys occupied habitat. For
                example, on May 18, 2010, a wildfire started in southeastern Crawford
                County within the Eldorado KWMA. The wildfire eventually burned a total
                of approximately 3,071 ha (7,588 ac), including 146 ha (362 ac) of
                occupied habitat (where 30 singing males were counted in 2009) and 36
                ha (90 ac) of young jack pine habitat that would have likely been
                occupied by Kirtland's warblers in 3 years (USFS 2010, pp. 1, 7, 11).
                The following year on June 7, 2011, lightning ignited a wildfire that
                destroyed approximately 49 ha (120 ac) of 11-year-old habitat in the
                Manistee River KWMA, where seven male Kirtland's warblers were counted
                during the 2011 census (MDNR, unpubl. data). Drought can cause
                mortality of jack pine seedlings (Rajasekaran and Blake 1999, p. 175)
                and reduce the density of jack pine trees (Kintigh 2011, pers. comm.).
                Drought can also stress older jack pines and make them more susceptible
                to insects and diseases (Kintigh 2011, pers. comm.). Fungal pests,
                including Gremmeniella abietina var. abietina, and Sphaeropsis sapinea
                (also known as Diplodia pinea), are known to cause mortality in jack
                pine trees (USFS and MDNR 1981, p. 14; Nicholls and Ostry 1990, p. 55).
                Jack pine budworm (Choristoneura pinus pinus), mountain pine beetle
                (Dendroctonus ponderosae), and jack pine sawfly (Neodiprion swainei)
                can also cause topkill and mortality in jack pine trees (McCullough
                2000, p. 252; Colgan and Erbilgin 2011, p. 426; Wilson 1971, p. 1).
                Generally, past impacts of these natural events on jack pines have had
                little effect on Kirtland's warbler habitat. Severe outbreaks of insect
                or fungal pests can have devastating effects on large areas of forest
                (e.g., the effect of emerald ash borer (Agrilus planipennis Fairmaire)
                on ash species (Fraxinus spp.)). Although there are no known imminent
                threats to Kirtland's warbler, emerging disease and pests warrant
                continued monitoring
                [[Page 54448]]
                because of the potential to harm significant amounts of managed
                habitat. Jack pine forests that serve as Kirtland's warbler habitat are
                under the oversight of forest-management agencies that closely track
                new forest diseases and pests and will take swift action if a newly
                emerging issue is detected.
                    We reviewed available information on the effects to Kirtland's
                warbler habitat from expanded development on private lands in or near
                breeding habitat. Although these factors and forest pests and diseases
                have the potential to affect Kirtland's warblers and their habitat,
                land management agencies have been successful in maintaining sufficient
                amounts of suitable habitat to support historically high numbers of
                Kirtland's warblers. While activities and natural processes (e.g.,
                wildfire, drought, development) that affect breeding habitat may still
                have some negative effects on individual Kirtland's warblers, the
                population of Kirtland's warblers appears resilient to these factors
                within the context of the current management regime. Furthermore,
                management efforts to date have been adaptive in terms of the acreage
                and spatial and temporal configuration of habitat needed to mitigate
                the effects associated with natural breeding habitat loss and
                fragmentation. The land management agencies have shown a commitment to
                Kirtland's warbler habitat management through their forest management
                plans as reflected in the 2016 MOU, agreeing to continue habitat
                management, and developing and implementing the Conservation Plan.
                Migration Habitat
                    Although Kirtland's warblers spend a relatively small amount of
                time each year migrating, the migratory period has the highest
                mortality rate of any phase of the annual cycle, accounting for 44
                percent of annual mortality (Rockwell et al. 2017, p. 722). Migratory
                survivorship levels are, however, above the minimum needed to sustain
                the population (Mayfield 1960, pp. 204-207; Berger and Radabaugh 1968,
                p. 170; Bocetti et al. 2002, p. 99; Rockwell et al. 2017, pp. 721-723;
                Trick, unpubl data). Recent research is refining our knowledge of
                spring and fall migration timing and routes for the Kirtland's warbler.
                Little is currently known about the importance of specific stopover
                sites and any factors affecting them, although coastal areas along the
                Great Lakes and Atlantic Ocean (e.g., western Lake Erie basin and the
                Florida and Georgia coasts) that appear important to migrating
                Kirtland's warblers are also areas where natural habitats have been
                highly fragmented by human development. At stopover sites within these
                highly fragmented landscapes, competition for food sources among long-
                distance passerine migrants is expected to be high, especially in
                fallout areas where many migrating birds land to rest, usually due to
                weather events or long flights over open water (Moore and Yong 1991,
                pp. 86-87; Kelly et al. 2002, p. 212; N[eacute]meth and Moore 2007, p.
                373). Increased competition may prolong stopover duration or increase
                the number of stopovers that are needed to complete migration between
                breeding and wintering grounds (Goymann et al. 2010, p. 480).
                    The quantity and quality of migratory habitat needed to sustain
                Kirtland's warbler numbers above the recovery goal of 1,000 pairs
                appears to be sufficient, based on a sustained and increasing
                population since 2001. If loss or destruction of migratory habitat were
                limiting or likely to limit the population to the degree that
                maintaining a healthy population may be at risk, it should be apparent
                in the absence of the species from highly suitable breeding habitat in
                the core breeding range. In fact, we have seen just the opposite:
                Increasing densities of breeding individuals in core areas and a range
                expansion into what would appear to be less suitable habitat elsewhere.
                This steady population growth and range expansion has occurred despite
                increased development and fragmentation of migratory stopover habitat
                within coastal areas.
                Wintering Habitat
                    Similar to the breeding grounds, the quantity and quality of
                wintering habitat needed to sustain Kirtland's warbler numbers above
                the recovery goal of 1,000 pairs appears to be sufficient, based on a
                sustained and increasing population since 2001. Compared to the
                breeding grounds, less is known about the wintering grounds in The
                Bahamas. Factors affecting Kirtland's warblers on the wintering
                grounds, as well as the magnitude of the impacts, remain somewhat
                uncertain. Few of the known Kirtland's warbler wintering sites
                currently occur on protected land. Rather, most Kirtland's warblers
                appear to winter more commonly in early successional habitats that have
                recently been or are currently being used by people (e.g., abandoned
                after clearing, grazed by goats), where disturbance has set back plant
                succession (Wunderle et al. 2010, p. 132). Potential threats to
                wintering habitat include habitat loss caused by human development,
                altered fire regime, changes in agricultural practices, and invasive
                plant species. The potential threats of rising sea level, drought, and
                destructive weather events, such as hurricanes on the wintering
                grounds, are discussed below under Factor E.
                    Tourism is the primary economic activity in The Bahamas, accounting
                for 65 percent of the gross domestic product, and The Bahamas' Family
                Islands Development Encouragement Act of 2008 supports the development
                of resorts on each of the major Family Islands (part of The Bahamas)
                (Moore and Gape 2009, p. 72). Residential and commercial development
                could result in direct loss of Kirtland's warbler habitat, especially
                on New Providence and Grand Bahama, which together support 85 percent
                of the population of Bahamian people (Moore and Gape 2009, p. 73;
                Wunderle et al. 2010, p. 135; Ewert 2011, pers. comm.). This loss could
                occur on both private and commonage lands (land held communally by
                rural settlements), as well as generational lands (lands held jointly
                by various family members).
                    Local depletion and degradation of the water table from wells and
                other water extraction and introduction of salt water through human-
                made channels or other disturbances to natural hydrologies may also
                negatively impact Kirtland's warblers by affecting fruit and arthropod
                availability (Ewert 2011, pers. comm.).
                    Fire may have positive or negative impacts on winter habitat,
                depending on the frequency, timing, and intensity of fires and where
                the fires occur. Fires are relatively common and widespread on the pine
                islands in the northern part of the archipelago and have increased
                since settlement, especially during the dry winter season when
                Kirtland's warblers are present (The Nature Conservancy 2004, p. 3).
                Fire may benefit Kirtland's warblers when succession of low coppice to
                tall coppice is set back (Currie et al. 2005b, p. 79) but may
                negatively impact wintering Kirtland's warblers if it results in
                reduced density and fruit production of understory shrubs (Currie et
                al. 2005b, p. 85).
                    Invasive plants are another potential factor that could limit the
                extent of winter habitat in The Bahamas. Brazilian pepper (Schinus
                terebinthifolius), jumbie bean (Leucaena leucocephala), Guinea grass
                (Panicum maximum), and Casuarina or Australian pine (Casuarina
                equisetifolia) may be the most important invasive species of immediate
                concern (Ewert 2011, pers. comm.; Wunderle 2018, pers. comm.). These
                aggressive plants colonize patches early after disturbances and may
                form monocultures, which preclude the establishment of fruit plant
                species heavily used by Kirtland's
                [[Page 54449]]
                warblers. Casuarina pine establishment can increase sand loss by out-
                competing native plants that stabilize dunes, resulting in increased
                coastal erosion and habitat loss (Sealey 2011, p. 12).
                    Some invasive species, such as jumbie bean, are good forage for
                goats. By browsing on these invasive plants, goats create conditions
                that favor native shrubs and may increase the density of native shrubs
                used by Kirtland's warblers (Ewert 2011, pers. comm.). Goat farming
                could play a role in controlling the spread of some invasive species at
                a local scale, while aiding in the restoration of native vegetation
                patches. Still, many plants such as royal poinciana (Delonix regia),
                tropical almond (Terminalia catappa), and morning glory (Ipomoea
                indica) are commonly imported for landscaping and have the potential to
                escape into the wild (Smith 2010, pp. 9-10; Ewert 2011, pers. comm.)
                and could displace native shrubs that provide fruit for Kirtland's
                warblers.
                    The Bahamas National Trust administers 32 national parks that cover
                more than 809,371 ha (2 million ac) (Bahamas National Trust 2017, p.
                3). Although not all national parks contain habitat suitable for
                Kirtland's warblers, several parks provide suitable wintering habitat,
                including the Leon Levy Native Plant Preserve on Eleuthera Island,
                Harrold and Wilson Ponds National Park on New Providence Island, and
                Exuma Cays Land and Sea Park on Hawksbill Cay (The Nature Conservancy
                2011, p. 2).
                    The Bahamas National Trust Act of 1959 and the National Parks
                Ordinance of 1992 established non-government statutory roles to the
                Bahamas National Trust and the Turks and Caicos Islands National Trust,
                respectively. These acts empower these organizations to hold and manage
                environmentally important lands in trust for their respective
                countries.
                    Simply protecting parcels of land or important wintering habitat,
                however, may be insufficient to sustain adequate amounts of habitat for
                the Kirtland's warbler because of the species' dependence on early
                successional habitat (Mayfield 1972, p. 349; Haney et al. 1998, p. 210;
                Sykes and Clench 1998, pp. 256-257; Wunderle et al. 2010, p. 124),
                which changes in distribution over time. In addition, food availability
                at any one site varies seasonally, as well as between years, and is not
                synchronous across all sites (Wunderle et al. 2010, p. 124). In the
                face of changes in land use and availability, sustaining sufficient
                patches of early-successional habitat for Kirtland's warbler in The
                Bahamas will likely require a landscape-scale approach (Wunderle et al.
                2010, p. 135).
                    Although threats to Kirtland's warblers on the wintering grounds
                exist as a result of habitat loss due to succession or development,
                hydrology changes, fire, and invasive species, the current extent and
                magnitude of these threats appears not to be significantly limiting
                Kirtland's warbler population numbers based on the species' continuous
                population growth over the last two decades.
                Habitat Distribution
                    The Kirtland's warbler has always occupied a relatively limited
                geographic range on both the breeding and wintering grounds. This
                limited range makes the species naturally more vulnerable to
                catastrophic events compared to species with wide geographic
                distributions, as having multiple populations in a wider distribution
                reduces the likelihood that all individuals will be affected
                simultaneously by a catastrophic event (e.g., large wildfire in
                breeding habitat, hurricane in The Bahamas). Since the species was
                listed, the geographic area where the Kirtland's warbler occurs has
                increased, reducing the risk to the species from catastrophic events.
                As the population continues to increase and expand in new breeding and
                wintering areas, the species will become less vulnerable to
                catastrophic events. The Conservation Plan, which land management
                agencies agreed to implement under the 2016 MOU, includes a goal to
                improve distribution of habitat across the breeding range to reduce
                this risk by managing lands in the Upper Peninsula of Michigan and in
                Wisconsin in sufficient quantity and quality to provide breeding
                habitat for 10 percent (100 pairs) or more of the goal of 1,000 pairs
                (MDNR et al. 2015, p. 23).
                B. Overutilization for Commercial, Recreational, Scientific, or
                Educational Purposes
                    The Kirtland's warbler is a non-game species, and no commercial
                harvest is known to occur in either the breeding or wintering grounds.
                Land management agencies within the Kirtland's warbler's breeding range
                previously had, and will continue to have, the ability to implement
                seasonal closures to specific areas for a variety of reasons and, when
                necessary, could limit access outside of designated roads and trails to
                further protect the species. Within the 23 KWMAs in the northern Lower
                Peninsula of Michigan and designated lands in Michigan's Upper
                Peninsula, approximately 71 km (44 miles) of routes are designated for
                off-road vehicle (ORV), all-terrain vehicle (ATV), or motorcycle use.
                In addition, approximately 151 km (94 miles) of trails are designated
                for hiking, biking, and horseback riding (USFWS, unpubl. data).
                Additionally, approximately 3,510 km (2,181 miles) of authorized
                ungraded and graded roads occur within the KWMAs (USFWS, unpubl. data).
                As described in the Conservation Plan (MDNR et al. 2015, p. 16),
                existing forest roads and trails have not typically been closed or
                otherwise restricted specifically because of the presence of adjacent
                Kirtland's warbler habitat.
                    On a few occasions (Enger 2007, pers. comm.; Kaiser 2014, pers.
                comm.), motor vehicles used on roads open to such use have collided
                with and killed Kirtland's warblers. In addition, the noise from roads
                has been shown to reduce breeding success of other passerines
                (Schroeder et al. 2012, pp. 6-7; Proppe et al. 2013, pp. 1080-1082) and
                could have similar negative effects to Kirtland's warblers. Any past
                direct and indirect effects of road use have not hindered progress
                toward recovering the Kirtland's warbler, however, and we do not
                anticipate a greater extent of effects related to recreation post-
                delisting. Because Kirtland's warblers occupy large blocks of habitat
                over long periods of time (Donner et al. 2010, p. 5), maintaining
                larger areas of habitat is a primary management goal (MDNR 2015, pp.
                33-34). Managing for larger blocks of breeding habitat reduces the
                effects of roads and trails that are on the edges of the habitat
                blocks.
                    A variety of State, national, and international laws protect
                Kirtland's warblers independent of their status under the ESA. Laws
                outside of the U.S. played an important role in helping to recover the
                species, and State laws will in some cases provide additional
                protections after delisting. The Kirtland's warbler is protected by the
                Migratory Bird Treaty Act of 1918 (MBTA; 16 U.S.C. 703-712). The MBTA
                prohibits take, capture, killing, trade, or possession of Kirtland's
                warblers and their parts, as well as their nests and eggs. The
                regulations implementing the MBTA further define ``take'' as to
                ``pursue, hunt, shoot, wound, kill, trap, capture, or collect'' or
                attempt those activities (50 CFR 10.12).
                    The States of Florida, Georgia, Indiana, Michigan, North Carolina,
                Ohio, Virginia, and Wisconsin list the Kirtland's warbler as
                endangered, under their respective State endangered species
                regulations. In Michigan, where the majority of the population breeds,
                part 365 of Public Act 451 of 1994 prohibits take, possession,
                [[Page 54450]]
                transportation, importation, exportation, processing, sale, offer for
                sale, purchase, or offer to purchase, transportation or receipt for
                shipment by a common or contract carrier of Kirtland's warblers or
                their parts.
                    The Kirtland's warbler was declared federally endangered in Canada
                in 1979. Canada's Species at Risk Act of 2003 (SARA) is the primary law
                protecting the Kirtland's warbler in Canada. SARA bans killing,
                harming, harassing, capturing, taking, possessing, collecting, buying,
                selling, or trading of individuals that are federally listed. SARA also
                extends protection to the residence (habitat) of individuals that are
                federally listed. In addition, the Kirtland's warbler is listed as
                endangered under Ontario's Endangered Species Act of 2007. Canada's
                Migratory Bird Convention Act of 1994 also provides protections to
                Kirtland's warblers. Under Canada's Migratory Bird Convention Act, it
                is unlawful to be in possession of migratory birds or nests, or to buy,
                sell, exchange, or give migratory birds or nests, or to make them the
                subject of commercial transactions.
                    In The Bahamas and the Turks and Caicos Islands, the Kirtland's
                warbler is recognized as a globally ``Near Threatened'' species but has
                no federally listed status. In The Bahamas, the Wild Birds Protection
                Act (chapter 249) allows the Minister of Wild Animals and Birds
                Protection to establish and modify reserves for the protection of any
                wild bird. The species is also protected in The Bahamas by the Wild
                Animals (Protection) Act (chapter 248) that prohibits the take or
                capture, export, or attempt to take, capture, or export any wild animal
                from The Bahamas. The Bahamas regulates scientific utilization of the
                Kirtland's warbler, based on recommendations previously provided by the
                Kirtland's Warbler Recovery Team (Bocetti 2011, pers. comm.).
                    Through the MBTA, SARA, laws in The Bahamas, and State laws, the
                species remains protected from pursuit, wounding, or killing that could
                potentially result from activities focused on the species in breeding,
                wintering, and migratory habitat (e.g., wildlife photography without
                appropriate care to ensure breeding birds can continue to feed and care
                for chicks and eggs normally and without injury to their offspring).
                C. Disease or Predation
                    There is no information of any disease impacting the Kirtland's
                warbler.
                    For most passerines, nest predation has the greatest negative
                impact on reproductive success and can affect entire populations
                (Ricklefs 1969, p. 6; Martin 1992, p. 457). Nest predation may be
                particularly detrimental for ground-nesting bird species in shrublands
                (Martin 1993, p. 902). Predation rates of Kirtland's warbler nests have
                ranged from 3 to 67 percent of nests examined (Mayfield 1960, p. 204;
                Cuthbert 1982, p. 1; Walkinshaw 1983, p. 120); however, few predation
                events have been directly observed, and, in general, evidence regarding
                the importance of certain nest or adult predators lack quantitative
                support (Mayfield 1960, p. 182; Walkinshaw 1972, p. 5; Walkinshaw 1983,
                pp. 113-114).
                    Overall, nest predation rates for Kirtland's warblers are similar
                to other passerines and are below levels that would compromise
                population replacement (Bocetti 1994, pp. 125-126; Cooper et al.,
                unpubl. data). The increasing numbers of domestic cats (Felis catus) in
                the breeding and wintering habitats is recognized (Lepczyk et al. 2003,
                p. 192; Horn et al. 2011, p. 1184), but there is not sufficient
                evidence to conclude at this time that predation from cats is currently
                having population-level impacts to the Kirtland's warbler.
                D. Inadequacy of Existing Regulatory Mechanisms
                    Under this factor, we examine the threats identified within the
                other factors as ameliorated or exacerbated by any existing regulatory
                mechanisms or conservation efforts. Section 4(b)(1)(A) of the ESA
                requires that the Service take into account ``those efforts, if any,
                being made by any State or foreign nation, or any political subdivision
                of a State or foreign nation, to protect such species.'' In relation to
                Factor D under the ESA, we interpret this language to require the
                Service to consider relevant Federal, State, and Tribal laws,
                regulations, and other such binding legal mechanisms that may
                ameliorate or exacerbate any of the threats we describe in threat
                analyses under the other four factors or otherwise enhance the species'
                conservation. Our consideration of the regulatory mechanisms addressing
                the threats to the species, is described where applicable in the
                relevant factor section (see discussion under Factors A, B, and E).
                E. Other Natural or Manmade Factors Affecting Its Continued Existence
                Pesticides
                    Pesticides have the potential to cause direct and indirect effects
                to non-target species, but we are not aware of any pesticides that are
                negatively affecting the Kirtland's warbler population. Kirtland's
                warblers could be exposed to pesticides on the breeding or wintering
                grounds or during migration. On the breeding grounds, forest managers
                are not routinely using any pesticides within occupied jack pine stands
                (Huber 2018, pers. comm.; Kintigh 2018, pers. comm.). For Kirtland's
                warbler, exposure to pesticides would be most likely through dietary
                exposure (treatment of insects or fruit plants) or accidental spray
                drift on the edges of suitable habitat.
                    The U.S. Environmental Protection Agency used Kirtland's warbler as
                a case study during the re-registration process for two organophosphate
                pesticides, chlorpyrifos and malathion (Moore et al. 2017, p. 1). A
                probabilistic model was developed to assess the risks of the two
                pesticides to the birds during the breeding season and migration. The
                model results predicted very low acute and chronic risk for these
                pesticides for Kirtland's warbler (Moore et al. 2017, p. 265). This
                conclusion is unsurprising, as Moore et al. (2017, p. 267) found that
                treatments do not occur on Kirtland's warbler breeding grounds and only
                rarely would warblers be exposed during migration.
                Brood Parasitism
                    Brood parasitism can depress reproduction of avian hosts in several
                ways, including the direct removal or predation of eggs or young,
                facilitating nest predation by other nest predators, reducing hatching
                or fledging success, altering host population sex ratios, and
                increasing juvenile and adult mortality beyond the nest (Elliot 1999,
                p. 55; Hoover 2003, pp. 928-929; Smith et al. 2003, pp. 777-780;
                Zanette et al. 2005, p. 818; Hoover and Reetz 2006, pp. 170-171; Hoover
                and Robinson 2007, p. 4480; Zanette et al. 2007, p. 220).
                    The brown-headed cowbird is the only obligate brood parasite within
                the Kirtland's warbler's breeding range and the only species documented
                parasitizing Kirtland's warbler nests. Two facultative interspecific
                nest parasite species, the black-billed cuckoo (Coccyzus
                erythropthalmus) and the yellow-billed cuckoo (Coccyzus americanus),
                may occur within the Kirtland's warbler's breeding range, but
                parasitism of a Kirtland's warbler nest has not been documented for
                these species and is not believed to be a threat.
                    Although brown-headed cowbirds were historically restricted to
                prairie ecosystems, forest clearing and agricultural development of
                Michigan's Lower Peninsula in the late 1800s
                [[Page 54451]]
                facilitated the brown-headed cowbird's range expansion into Kirtland's
                warbler nesting areas (Mayfield 1960, p. 145) such that brown-headed
                cowbirds were common within the Kirtland's warbler's breeding range by
                the early 1900s (Wood and Frothingham 1905, p. 49). The first known
                instance of brood parasitism of a Kirtland's warbler nest occurred in
                Crawford County, Michigan, in 1908 (Strong 1919, p. 181). Shortly
                thereafter, the scarcity of Kirtland's warblers was attributed to
                brown-headed cowbird parasitism (Leopold 1924, p. 57), which later data
                confirmed as significantly affecting the survival of the Kirtland's
                warbler (Mayfield 1960, pp. 180-181).
                    The Kirtland's warbler is particularly sensitive to brown-headed
                cowbird brood parasitism. The warbler's limited breeding range likely
                exposes the entire population to brown-headed cowbird parasitism
                (Mayfield 1960, pp. 146-147; Trick, unpubl. data). In addition, the
                peak egg-laying period of the brown-headed cowbird completely overlaps
                with that of the Kirtland's warbler, and the majority of Kirtland's
                warblers produce only one brood each year (Mayfield 1960, pp. 151-152;
                Radabaugh 1972, p. 55; Rockwell, unpubl. data). Kirtland's warblers
                have limited evolutionary experience with brown-headed cowbirds
                compared to other hosts and have not developed effective defensive
                behaviors to thwart brood parasitism (Walkinshaw 1983, pp. 157-158).
                    Between 1903 and 1971, observed parasitism rates of Kirtland's
                warbler nests ranged from 48 percent to 86 percent (reviewed in Shake
                and Mattson 1975, p. 2). Brown-headed cowbirds also appear to exert
                greater pressure on Kirtland's warbler nests than other passerines
                within the same breeding habitat, with 93 percent of brown-headed
                cowbird eggs found in jack pine habitat placed in Kirtland's warbler
                nests compared to all other host species combined (Walkinshaw 1983, p.
                154). Kirtland's warbler fledging rates averaged less than one young
                per nest prior to the initiation of brown-headed cowbird control
                (Walkinshaw 1972, p. 5).
                    The effect of brown-headed cowbird parasitism exacerbated negative
                impacts associated with habitat loss in the decline of the Kirtland's
                warbler population (Rothstein and Cook 2000, p. 7). Once trapping of
                brown-headed cowbirds within Kirtland's warbler nesting areas was
                demonstrated to decrease parasitism rates and increase Kirtland's
                warbler nesting success (Cuthbert 1966, pp. 1-2), intensive brown-
                headed cowbird removal was recommended on major Kirtland's warbler
                nesting areas as one of the necessary steps for the recovery of the
                Kirtland's warbler (Shake and Mattsson 1975, p. 2).
                    Starting in 1972, the Service, in conjunction with the USDA-WS,
                MDNR, and USFS, implemented an intensive brown-headed cowbird control
                program within Kirtland's warbler nesting areas in Michigan's Lower
                Peninsula. On average, the control program annually removes
                approximately 3,573 brown-headed cowbirds from occupied Kirtland's
                warbler habitat in northern lower Michigan (USDA-WS 2016, unpubl.
                report). Recent trap rates, however, have been below 1,500 brown-headed
                cowbirds per year (USDA-WS, unpubl. data).
                    Following the initiation of brown-headed cowbird control in
                northern lower Michigan in 1972, brood parasitism rates decreased to
                6.2 percent, and averaged 3.4 percent between 1972 and 1981 (Kelly and
                DeCapita 1982, p. 363). Kirtland's warbler fledging rates
                simultaneously increased from less than one per nest to 2.8 per nest,
                and averaged 2.78 young fledged per nest between 1972 and 1981 (Kelly
                and DeCapita 1982, pp. 364-365). Had brown-headed cowbird parasitism
                not been controlled, the Kirtland's warbler population may have been
                reduced to only 42 pairs by 1974 (Mayfield 1975, p. 43).
                    Brood parasitism of Kirtland's warbler nests also occurs in
                Wisconsin, and brown-headed cowbird trapping is conducted in select
                Kirtland's warbler breeding areas. The trapping program in Wisconsin
                started in 2008, and is run using similar methods to the program in
                Michigan, with an average of 238 brown-headed cowbirds captured per
                year (USDA-WS, USFWS unpubl. data). In 2007, two of three Kirtland's
                warbler nests were parasitized (USFWS, unpubl. data). After the
                initiation of brown-headed cowbird control in 2008, brood parasitism
                rates in Wisconsin have fluctuated substantially among years, from 10
                percent to 66 percent (USFWS, unpubl. data; Trick, unpubl. data).
                However, in the same time period (2008-2017), overall nest success has
                ranged from 19 to 80 percent, and the average fledge rate was estimated
                to be between 1.51 to 1.92 chicks per nest (USFWS 2017, pp. 2-3).
                    Limited studies on the effectiveness of the brown-headed cowbird
                control program in relation to Kirtland's warbler nest productivity in
                Michigan have been conducted since the early 1980s. Brown-headed
                cowbirds were nearly eliminated in areas directly adjacent to a trap,
                and brown-headed cowbird densities increased 5 km (3 miles) and greater
                from brown-headed cowbird removal areas (De Groot and Smith 2001, p.
                877). Brown-headed cowbird densities also significantly increased at
                distances greater than 10 km (6 miles) from brown-headed cowbird
                removal areas, further demonstrating the localized effect of brown-
                headed cowbird control (De Groot and Smith 2001, p. 877). Although
                brown-headed cowbird density increased with distance beyond 5 km (3
                miles) of brown-headed cowbird traps, brown-headed cowbird densities
                were still low in those areas compared to other parts of North America
                (De Groot and Smith 2001, p. 877). Anecdotal observations of brood
                parasitism rates within Kirtland's warbler nesting areas during periods
                of brown-headed cowbird control indicated very low levels of brood
                parasitism; parasitism rates have been reduced to less than 1 percent
                of all nests in areas where trapping occurred (Bocetti 1994, p. 96;
                Rockwell 2013, pp. 80, 93; Rockwell, unpubl. data).
                    A study is currently underway in Michigan to evaluate the effective
                range of a brown-headed cowbird trap and to determine the brood
                parasitism rate of Kirtland's warbler nests when traps are not operated
                during the warbler's breeding season. Beginning in 2015, 12 brown-
                headed cowbird traps (out of 55 total) were closed for two breeding
                seasons. In 2015, only one nest out of 157 was parasitized,
                approximately 4.6 km (2.9 miles) away from the nearest brown-headed
                cowbird trap. In 2016, similar low rates of parasitism were observed,
                with only 2 parasitized nests out of 128. Due to the low levels of
                brood parasitism observed, an additional 6 traps were closed in 2017,
                and none of the 100 nests observed between 0.5 and 22.1 km (0.3 and
                13.7 miles) from a brown-headed cowbird trap in 2017 were parasitized
                (Cooper et al., unpubl. data). In total, only 3 of 385 Kirtland's
                warbler nests were parasitized in areas with a spatially reduced
                trapping program from 2015 to 2017. These preliminary data corroborate
                similar findings that the effective range of a brown-headed cowbird
                trap is likely much larger than the range (i.e., 1.6 km (1 mile)
                radius) traditionally used in planning and implementing the brown-
                headed cowbird control program. Following these results, all brown-
                headed cowbird trapping in Michigan's northern Lower Peninsula was
                suspended for the 2018 nesting season. Only 1 of 129 Kirtland's warbler
                nests was found to be
                [[Page 54452]]
                parasitized (Cooper et al., unpubl. data) in 2018.
                    Trend estimate data from Breeding Bird Survey routes between 2005
                and 2015 show decreasing brown-headed cowbird populations in Michigan
                and the Upper Great Lakes (Sauer et al. 2017, p. 169). Reduced brown-
                headed cowbird abundance within Kirtland's warbler nesting areas is
                supported by results from point count surveys conducted between 2015
                and 2018 in Kirtland's warbler nesting areas in Michigan's northern
                Lower Peninsula where brown-headed cowbird traps were not being
                operated. Only 67 brown-headed cowbirds were observed during 1,134
                point count surveys (Cooper et al., unpubl. data).
                    However, in similar experiments where brown-headed cowbird trapping
                was reduced or brought to an end following a lengthy period of
                trapping, brood parasitism rates elevated or returned to pre-trapping
                rates. Research at Fort Hood Military Reservation in Texas showed that
                after 3 years of decreased brown-headed cowbird trapping levels,
                parasitism rates increased from 7.9 percent to 23.1 percent and
                resulted in black-capped vireo (Vireo atricapilla) nest survival
                decreasing to unsustainable levels (Kostecke et al. 2009, p. 1). Other
                studies have found similar results with parasitism frequency and host
                bird productivity returning to pre-trapping levels quickly upon
                discontinuing cowbird removal (Kosciuch and Sandercock 2008, p. 546).
                    After 45 years of brown-headed cowbird trapping in Michigan, the
                threat of brood parasitism on the Kirtland's warbler has been greatly
                reduced but not eliminated. Brown-headed cowbirds remain present, but
                potentially in lower numbers, in jack pine habitat away from brown-
                headed cowbird traps, even if that area had been trapped in previous
                years (DeGroot and Smith 2001, p. 877; Bailey 2007, pp. 97-98; Cooper
                et al., unpubl. data). Female brown-headed cowbirds are highly
                prolific, estimated to produce up to 40 eggs in a breeding season
                (Scott and Ankney 1980, p. 680). Successful brown-headed cowbird
                reproduction outside of trapped areas may maintain a population of
                adult brown-headed cowbirds that could return in subsequent years with
                the ability to parasitize Kirtland's warbler nests. It is unclear if
                reduced parasitism rates are a permanent change to the landscape of
                northern lower Michigan. The best available information, however,
                indicates that cowbird removal efforts can be reduced, at least
                temporarily, without adversely impacting Kirtland's warbler
                productivity rates. Given the historical impact that the brown-headed
                cowbird has had on the Kirtland's warbler, and the potential for the
                brown-headed cowbird to negatively affect the warbler, a sustainable
                Kirtland's warbler population depends on monitoring the magnitude and
                extent of brood parasitism and subsequently adjusting the level of
                cowbird trapping appropriately.
                    The MOA (see Recovery and Recovery Plan Implementation, above)
                established in 2015 between the Service and MDNR addresses the
                commitment and long-term costs associated with future efforts to
                control brown-headed cowbirds. The MOA established a dedicated account
                from which income can be used to implement cowbird management and other
                conservation actions for the Kirtland's warbler. To date, the account
                has greater than $2.1 million invested for long-term growth. The MDNR
                has re-confirmed their commitment to implement and administer the
                brown-headed cowbird management program once the species is delisted
                (MDNR 2017). Given our understanding of the status of brown-headed
                cowbirds in northern lower Michigan, the $2.1 million investment,
                coupled with the MDNR's commitment, is sufficient to provide an
                effective brown-headed cowbird management program into the foreseeable
                future.
                Climate Change
                    Our analyses under the ESA include consideration of ongoing and
                projected changes in climate. A recent compilation of climate change
                and its effects is available from reports of the Intergovernmental
                Panel on Climate Change (IPCC) (IPCC 2014, entire). In our analyses, we
                use our expert judgment to weigh relevant information, including
                uncertainty, in our consideration of various aspects of climate change.
                    The effects of climate change on Kirtland's warblers were not
                identified as a threat to the species in the listing rule (32 FR 4001;
                March 11, 1967) or in the updated recovery plan (USFWS 1985, entire).
                Potential effects of climate change to the Kirtland's warbler could
                occur as a result of changes on the breeding or wintering grounds and
                include a decrease and shift in suitable breeding habitat outside of
                the species' current range (Prasad et al. 2007, unpaginated), increase
                in pests or pathogens of jack pine, a decrease in the extent of
                wintering habitat, and decoupling of the timing of migration from food
                resource peaks that are driven by temperature and are necessary for
                migration and feeding offspring (van Noordwijk et al. 1995, p. 456;
                Visser et al. 1998, pp. 1869-1870; Thomas et al. 2001, p. 2598; Strode
                2003, p. 1142).
                    Breeding Grounds: On the breeding grounds, climate change
                projections, based on low (B1) and high (A1FI) emission scenarios,
                predict shifts in mean temperature and precipitation as well as altered
                timing and extremes (Handler et al. 2014, pp. 68-84; Janowiak et al.
                2014, pp. 66-85; GLISA 2018, unpaginated). In the core breeding area,
                temperatures are expected to increase across all seasons, with more
                dramatic increases during winter months (Handler et al. 2014, p. 72).
                Precipitation is projected to increase in winter and spring but may
                decrease in the summer (Handler et al. 2014, pp. 73-75), with more
                extreme precipitation events representing a larger proportion of the
                total annual and seasonal rainfall (Handler et al. 2014, p. 82).
                    The extent and availability of suitable Kirtland's warbler habitat
                within jack pine forests on the breeding grounds could change based on
                projected changes to temperature and precipitation. The Forest
                Service's Forest Ecosystem Vulnerability Assessments considered impacts
                to above-ground biomass for 26 tree species, and projected stable (in
                Wisconsin) or slight reductions (in Michigan) in the biomass of jack
                pine over the next 50 years, with more significant declines projected
                by the end of the 21st century (Handler et al. 2014, p. 94; Janowiak et
                al. 2014, p. 99). In addition to a possible reduction in the biomass of
                jack pine, the spatial distribution of the species may also shift in
                response to changing climate.
                    The projections of how jack pine will be affected by climate change
                vary based on the model used and emission scenario considered. Overall,
                models predict that jack pine occurrence will contract in the northern
                Lower Peninsula and shift out of peripheral breeding areas. Scenarios
                using both low (B1) and high (A1F1) greenhouse gas emissions predicted
                a reduction of the extent of jack pine in Michigan but an expansion of
                jack pine in western Wisconsin and Minnesota (Prasad et al. 2007,
                unpaginated). More recent models using emission scenarios with
                Representative Concentration Pathways (RCPs) of 4.5 and 8.5 similarly
                projected a decline in jack pine occurrence in Michigan and indicated
                declines in northern Minnesota, northern Wisconsin, and the Upper
                Peninsula of Michigan (Donner et al. 2018, pp. 270-273). However,
                conditions were projected to remain suitable for jack pine occupancy in
                northern lower Michigan (Donner et al. 2018, pp. 271).
                [[Page 54453]]
                    Insect pests may become more problematic to jack pine under future
                climatic changes, with increasing damage and spread of new jack pine
                pests in the Kirtland's warbler's habitat areas. A warmer climate may
                increase the susceptibility of current jack pine forests to damage from
                pests and diseases (Bentz et al. 2010, pp. 606-610; Cudmore et al.
                2010, pp. 1040-1042; Safranyik et al. 2010, p. 432) and may allow for
                new pests such as western bark beetle to arrive (Handler et al. 2014,
                p.130). Forest managers will continue to monitor pest and pathogen
                outbreaks in jack pine forests.
                    Competition with deciduous forest species is also expected to favor
                an expansion of the deciduous forest into the southern portions of the
                boreal forest (USFWS 2009, p. 14) and affect interspecific
                relationships between the Kirtland's warbler and other wildlife
                (Colwell and Rangel 2009, p. 19657; Wiens et al. 2009, p. 19729).
                However, warmer weather and increased levels of carbon dioxide could
                also lead to an increase in tree growth rates on marginal forestlands
                that are currently temperature-limited (NAST 2000, p. 57). Higher air
                temperatures will cause greater evaporation and, in turn, reduce soil
                moisture, resulting in conditions conducive to forest fires (NAST 2000,
                p. 57) that favor jack pine propagation. Too much change in the fire
                regime could have a negative effect on jack pine regeneration and
                result in a shift to barrens (Handler et al. 2014, p. 130).
                Additionally, warmer temperatures could also lead to greater moisture
                stress, through accelerated litter layer decomposition leading to lower
                water-holding capacity (Handler et al. 2014, p. 130). Alternatively,
                warmer conditions and longer growing seasons could benefit pine
                forests, if carbon dioxide fertilization boosts long-term water-use
                efficiency and productivity (Handler et al. 2014, pp. 102, 114-115,
                130).
                    Recent vulnerability analyses estimate moderate potential impacts
                to jack pine forests as a result of the effects of climate change and
                low-moderate adaptive capacity of jack pine, based on its high
                tolerance for disturbance and existing management practices (Handler et
                al. 2014, p. 130). A climate change vulnerability assessment for
                wildlife species by MDNR (Hoving et al. 2013, p. 40), using
                NatureServe's Climate Change Vulnerability Index, categorized
                Kirtland's warbler as ``Presumed Stable,'' with the caveat that while
                the population may remain stable, its range may shift outside of
                Michigan.
                    In summary, there may be a reduction or a shift in available
                suitable jack pine habitat over the next 50 years, but these reductions
                may be offset to some degree by other ecosystem processes, such as an
                altered fire regime and adaptive habitat management (harvest of jack
                pines and techniques, such as the use of containerized saplings rather
                than bare-root stock, for planting jack pine plantations). Jack pine
                may also adapt to changing climatic conditions. As suitable habitat
                shifts, Kirtland's warblers could also adapt by utilizing more marginal
                habitat, or increasing in density in high-quality habitat. The KWCT
                will continue to analyze the extent and distribution of suitable
                habitat, and the effects of pests and disease on jack pine.
                    Wintering Grounds: On the wintering grounds, effects of climate
                change to the Kirtland's warbler could occur as a result of changing
                temperature and precipitation, rising sea levels, and storm events. For
                migratory species, unfavorable changes on the wintering grounds can
                result in subsequent negative effects on fitness later in the annual
                life cycle (Marra et al. 1998, p. 1885; Sillett et al. 2000, pp. 2040-
                2041; Rockwell et al. 2012, pp. 747-748; Rockwell et al. 2017, p. 721).
                For the Kirtland's warbler, wintering habitat condition affects
                survival and reproduction (Rockwell et al. 2012, pp. 747-748; Rockwell
                et al. 2017, p. 721). These effects likely result from limited resource
                availability on the wintering grounds that reduces body condition and
                fat reserves necessary for successful migration and reproduction
                (Wunderle et al. 2014, pp. 47-49). The availability of sufficient food
                resources is affected by the amount of habitat for arthropods and
                fruiting plants, temperature, and precipitation (Brown and Sherry 2006,
                pp. 25-27; Wunderle et al. 2014, p. 39).
                    Temperatures in the Caribbean have shown strong warming trends
                across all regions, particularly since the 1970s (Jones et al. 2016,
                pp. 3325, 3332), and are likely to continue to warm. A climate model
                with a high emission scenario (A2) predicted an increase in temperature
                of almost 2.5 to 3.0 degrees Celsius (4.5 to 6.3 degrees Fahrenheit)
                above the mean temperatures of 1970-1989 by the 2080s (Karmalkar et al.
                2013, p. 301). Climate change models using a lower emissions scenario
                (RCP4.5) project an increase in surface temperature in the Caribbean
                ranging from 1.2 to 1.9 degrees Celsius (2.2 to 3.4 degrees Fahrenheit)
                for 2081-2100 when compared to 1986-2005 (Nurse et al. 2014, p. 1628).
                Other models, using high (A2) and low (B2) emission scenarios, also
                predicted an increase in the number of warm days and nights and a
                decrease in the frequencies of cool days and nights, in addition to
                higher mean daily temperatures, for 2071-2099 relative to 1961-1999
                (Stennett-Brown et al. 2017, pp. 4838-4840). Increased temperatures
                could affect food availability by altering food supply (arthropod and
                fruit availability), although it is unknown to what extent the
                predicted increases in temperature would increase or decrease food
                supply for the Kirtland's warbler. Other effects of increasing
                temperature related to sea level and precipitation are described below.
                    Increasing temperatures can contribute to sea level rise from the
                melting of ice over land and thermal expansion of seawater. A wide
                range of estimates for future global mean sea level rise is found in
                the scientific literature (Church et al. 2013, entire; IPCC 2013a,
                entire; Simpson et al. 2010, pp. 55-61; Sweet et al. 2017, entire). By
                2070, global mean sea level is projected to increase by 0.35 m (1.15
                ft) to 0.42 m (1.38 ft) under RCP4.5 and RCP8.5 scenarios (IPCC 2013a,
                p. 1445). Another model predicts increases in sea level ranging from
                0.35 m (1.15 ft) to 0.79 m (2.59 ft) by 2070 under comparable emission
                scenarios (Sweet et al. 2017, p. 23). An increase in sea level could
                reduce the availability of suitable habitat due to low-elevation areas
                being inundated, resulting in a reduction in the size of the islands on
                which Kirtland's warblers winter (Amadon 1953, p. 466; Dasgupta et al.
                2009, pp. 21-23). The Bahamas archipelago is mainly composed of small
                islands, and more than 80 percent of the landmass is within 1.5 m (4.9
                ft) of mean sea level (The Bahamas Environment, Science and Technology
                Commission 2001, p. 43). This makes The Bahamas particularly vulnerable
                to future rises in sea level (Simpson et al. 2010, p. 74), which could
                result in a reduction of the extent of winter habitat and negatively
                impact the Kirtland's warbler. Estimates of total landmass loss
                throughout The Bahamas due to a 1-meter (3.3 ft) rise in sea level vary
                from 5 percent (Simpson et al. 2010, p. 77) to 11 percent (Dasgupta et
                al. 2007, p. 12; 2009, p. 385). However, not all of the land that may
                be inundated is potentially suitable for Kirtland's warbler (e.g.,
                developed land, closed-canopy forest). To assess how climate change
                scenarios may affect Kirtland's warbler's wintering habitat, we
                considered a recent estimate of potential Kirtland's warbler habitat
                loss due to sea level rise (Wolcott et al. 2018, entire). Loss of open-
                land habitat varied across the archipelago, based on elevational
                differences (Wolcott et al. 2018, p. 10). There have historically
                [[Page 54454]]
                been few observations of Kirtland's warblers on the northern islands
                (Cooper et al. 2019, p. 84), where elevations are lower and where
                projections indicate the greatest loss of open land (Wolcott et al.
                2018, p. 10). On Eleuthera, the island with the greatest known density
                of overwintering Kirtland's warblers, a rise in sea level of 1 meter
                (3.3 ft) or 2 meters (6.6 ft) would result in a loss of potential
                Kirtland's warbler wintering habitat of 0.8 percent and 2.6 percent,
                respectively (Wolcott et al. 2018, p. 9). Given that the projected rise
                in sea level in the foreseeable future is less than 1 meter (3.3 ft),
                we anticipate the loss of potential Kirtland's warbler winter habitat
                on Eleuthera due to sea level rise will be less than 0.8 percent.
                    Generally, climate models predict a drying trend in the Caribbean,
                but there is considerable temporal and spatial variation and often
                disagreement among models regarding specific predictions that make it
                difficult to determine the extent to which reduced rainfall or timing
                of rainfall may affect the Kirtland's warbler in the future. We
                reviewed available literature examining precipitation trends and
                projections in the Caribbean, and specifically The Bahamas, to assess
                the potential effects of changes in precipitation.
                    Precipitation patterns in the Caribbean from 1979 to 2012 did not
                show statistically significant century-scale trends across regions, but
                there were periods of up to 10 years when some regions were drier or
                wetter than the long-term averages (Jones et al. 2016, p. 10). In the
                northern Caribbean (which includes The Bahamas, Cuba, Jamaica, Haiti,
                Dominican Republic, and Puerto Rico), some years were more wet than the
                average, and other years were more dry across all seasons (Jones et al.
                2016, p. 3314), with higher precipitation totals since about 2000.
                Within The Bahamas, precipitation trends during the dry season
                (November through April) showed a significant drying trend for 1979-
                2009 (Jones et al. 2016, pp. 3328, 3331).
                    Model projections under two emission scenarios (RCP4.5 and 8.5)
                found that the projected precipitation varied seasonally and spatially
                throughout the islands of The Bahamas, both in the mid-term (2050) and
                long-term (2100) (Wolcott et al. 2018, pp. 4-6). The northern and
                north-central islands are likely to have increased precipitation in
                March (compared to baseline conditions), whereas the central islands
                are likely to become drier (Wolcott et al. 2018, p. 7-8) under both
                emission scenarios, with the magnitude of projected changes greater in
                RCP8.5.
                    Accurately projecting future precipitation trends in the Caribbean
                is difficult due to the complex interactions between sea surface
                temperatures, atmospheric pressure at sea level, and predominant wind
                patterns. Further, some models have difficulty accurately simulating
                the semi-annual seasonal cycle of precipitation observed in the
                Caribbean (Karmalkar et al. 2013, pp. 300-302). Recent models using
                statistical downscaling techniques have improved resolution but still
                show limitations for predicting precipitation (Stennett-Brown et al.
                2017, p. 4840). Thus, rainfall projections where Kirtland's warblers
                overwinter have limited certainty and should be interpreted with
                caution. Understanding the likely projected precipitation in The
                Bahamas and Caribbean is important because of the strong link between
                late winter rainfall and fitness of Kirtland's warblers. A drying trend
                on the wintering grounds will likely cause a corresponding reduction in
                available food resources (Studds and Marra 2007, pp. 120-121; Studds
                and Marra 2011, pp. 4-6). Rainfall in the previous month was an
                important factor in predicting fruit abundance (both ripe and unripe
                fruit) for wild sage and black torch in The Bahamas (Wunderle et al.
                2014, p. 19), which is not surprising given the high water content (60-
                70 percent) of their fruit (Wunderle, unpubl. data, cited in Wunderle
                et al. 2014, p. 4). Carry-over effects of weather on the wintering
                grounds, particularly late-winter rainfall, have been shown to affect
                spring arrival dates, reproductive success, and survival rates of
                Kirtland's warblers (reviewed in Wunderle and Arendt 2017, pp. 5-12;
                Rockwell et al. 2012, p. 749; Rockwell et al. 2017, pp. 721-722).
                    Decreases in rainfall and resulting decreases in food availability
                may also result in poorer body condition prior to migration. The need
                to build up the necessary resources to successfully complete migration
                could, in turn, result in delays to spring departure in dry years
                (Wunderle et al. 2014, p. 16) and may explain observed delays in
                arrival times following years with less March rainfall in The Bahamas
                (Rockwell et al. 2012, p. 747). Delays in the spring migration of
                closely related American redstarts (Setophaga ruticilla) have also been
                directly linked to variation in March rainfall and arthropod biomass
                (Studds and Marra 2007, p. 120; Studds and Marra 2011, p. 4), and have
                also resulted in fewer offspring produced per summer (Reudink et al.
                2009, p. 1624). These results strongly indicate that environmental
                conditions modify the timing of spring migration, which likely carries
                a reproductive cost. If The Bahamas experience a significant winter
                drying trend, Kirtland's warblers may be pressured to delay spring
                departures, while simultaneously contending with warming trends in
                their breeding range that pressure them to arrive earlier in the
                spring. Projection population modeling (Rockwell et al. 2017, p. 2)
                estimated a negative population growth in Kirtland's warbler as a
                result of a reduction of more than 12.4 percent from the current mean
                levels in March rainfall.
                    A recent drought in the Caribbean from 2013 to 2016, due in part to
                El Ni[ntilde]o, resulted in some of the highest temperatures and
                potential evapotranspiration anomalies observed in the region (Herrera
                and Ault 2017, p. 7822). As a result, it has been characterized as the
                most severe drought in the region since at least 1950 (Herrera and Ault
                2017, p. 7822) and may have been appreciably more severe because of
                anthropogenic warming (i.e., 15 to 17 percent of the drought's severity
                and approximately 7 percent of its spatial extent could be attributed
                to the anthropogenic effects of climate change) (Herrera et al. 2018,
                pp. 4-5). Future droughts are predicted to be increasingly severe
                because of higher temperatures, which played an important role in the
                2013-2016 drought, regardless of changes in precipitation (Herrera et
                al. 2018, p. 7). For the period during and following the 2013-2016
                drought, the Kirtland's warbler population remained stable or
                increased, indicating at least some level of resilience to severe,
                short-term drought.
                    Extreme weather events, such as tropical storms and hurricanes,
                will continue to occur with an expected reduction in the overall
                frequency of weaker tropical storms and hurricanes and an increase in
                the frequency of the most intense hurricanes (category 4 and 5
                hurricanes), based on several dynamical climate-modeling studies of
                Atlantic basin storm frequency and intensity (Bender et al. 2010, p.
                456; Knutson et al. 2010, pp. 159-161; Murakami et al. 2012a, pp. 2574-
                2576; Murakami et al. 2012b, pp. 3247-3253; Knutson et al. 2013, pp.
                6599-6613; Knutson et al. 2015, pp. 7213-7220). Although very intense
                hurricanes are relatively rare, they inflict a disproportionate impact
                in terms of storm damage (e.g., approximately 93 percent of damage
                resulting from hurricanes is caused by only 10 percent of the storms
                (Mendelsohn et al. 2012,
                [[Page 54455]]
                p. 3)). An increasing trend for hurricanes to have decreased forward or
                translational speeds may increase the future risk of heavy rainfall
                events and extended period of hurricane-force winds over an island
                (Kossin 2018, p. 105). This could result in future increased risks to
                Kirtland's warblers and their winter habitat.
                    Hurricanes have the potential to result in direct mortality of
                Kirtland's warblers during migration and while on the wintering grounds
                (Mayfield 1992, p. 11), but most birds do not arrive in The Bahamas
                until mid-October to early November, after peak hurricane season
                (Wunderle and Ewert 2018, p. 1). There is a high risk of short-term
                effects following the hurricane due to altered shelter and food (Wiley
                and Wunderle 1993, pp. 331-336). During recent observations of
                hurricane effects on the island of San Salvador, post-hurricane
                declines of Kirtland's warblers relative to previous winters may have
                been due to food resource loss resulting from salt spray that killed
                leaves and possibly arthropods and fruit (Wunderle and Ewert 2018, p.
                1). Because Kirtland's warblers readily shift sites on the wintering
                grounds based on food availability, Kirtland's warblers would likely be
                able to shift locations within and possibly between nearby islands as
                an immediate post-hurricane response (Wunderle et al. 2007, p. 124).
                Further, hurricanes likely produce new wintering habitat for Kirtland's
                warblers by opening up closed canopy habitat of tall coppice and may
                also help set back succession for existing suitable habitat (Wunderle
                et al. 2007, p. 126). Coastal areas at most risk to storm surges (and
                thus less suitable for development) may provide future habitat for
                Kirtland's warblers (Wunderle and Ewert 2018, p. 1).
                    In summary, uncertainties in modeling the projected effects of
                climate change in The Bahamas, both spatially and temporally, create
                some uncertainty in effects on the Kirtland's warbler's wintering
                habitat and food availability. There is more confidence that
                temperatures are likely to increase, and it is possible that there will
                be a drying trend over much of the Caribbean. However, it is not clear
                whether all islands will be equally affected by less precipitation. The
                Kirtland's warbler population has increased dramatically during the
                past drying trend (1979-2009) and recent drought (2013-2016) at its
                wintering grounds. In addition, individual warblers have been reported
                wintering outside of The Bahamas (see Distribution, above). Although
                the extent of behavioral plasticity and adaptive capacity at the
                species level to shift locations in response to the effects of climate
                change in the Caribbean remains unknown, as a long-distance migrant,
                the Kirtland's warbler is well suited, in terms of its movement
                patterns and dispersal ability, to reach other locations both within
                and outside of its current winter range where suitable winter habitat
                and food resources may be more available under future temperature and
                precipitation conditions.
                Collision With Lighted and Human-Made Structures
                    Collision with human-made structures (e.g., tall buildings,
                communication towers, wind turbines, power lines, and heavily lighted
                ships) kills or injures millions of migrating songbirds annually
                (Bocetti 2011, pp. 177-178; reviewed in Drewitt and Langston 2008, p.
                259; Longcore et al. 2008, pp. 486-489). Factors that influence the
                likelihood of avian collisions with human-made structures include size,
                location, use of lighting, and weather conditions during migratory
                periods (reviewed in Drewitt and Langston 2008, p. 233). The presence
                of artificial light at night and plate-glass windows are the most
                important factors influencing avian collisions with existing human-made
                structures (Ogden 1996, p. 4).
                    There are five confirmed reports of Kirtland's warblers colliding
                with human-made structures, all of which resulted in death. Two of
                these deaths resulted from collisions with windows (Kleen 1976, p. 78;
                Kramer 2009, pers. comm.), and three resulted from collisions with a
                lighted structure, including a lighthouse (Merriam 1885, p. 376), an
                electric light mast (Jones 1906, pp. 118-119), and a lighted monument
                (Nolan 1954). Another report of a Kirtland's warbler that flew into a
                window and appeared to survive after only being stunned by the
                collision (Cordle 2005, p. 2) was not accepted as an official
                documented observation of a Kirtland's warbler (Maryland Ornithological
                Society 2010, unpaginated).
                    Some bird species may be more vulnerable to collision with human-
                made structures than others due to species-specific behaviors.
                Particularly vulnerable species include: Night-migrating birds that are
                prone to capture or disorientation by artificial lights because of the
                way exposure to a light field can disrupt avian navigation systems;
                species that habitually make swift flights through restricted openings
                in dense vegetation; and species that are primarily active on or near
                the ground (reviewed in Ogden 1996, p. 8; Gauthreaux and Belser 2006,
                p. 67). Of the avian species recorded, the largest proportion of
                species (41 percent) that suffer migration mortality at human-made
                structures belong to the wood warbler subfamily (Parulinae), of which
                many species exhibit the above-mentioned behaviors (Ogden 1996, p. 14).
                    The Kirtland's warbler belongs to the Parulidae family, migrates at
                night, typically occupies dense vegetation, and is often active on or
                near the ground. Although Kirtland's warblers exhibit behavioral traits
                that may contribute to vulnerability to collision with human-made
                structures, little is known regarding how prone this species is to
                collision. The majority of bird collisions go undetected because
                corpses land in inconspicuous places or are quickly removed by
                scavengers, postmortem (Klem 2009, p. 317). Additionally, while most
                avian collisions take place during migration, detailed information
                about Kirtland's warbler migration is still limited. The Kirtland's
                warbler population is also small, reducing the probability of collision
                observations by chance alone, compared to other species. These factors
                have inhibited the gathering of information, and in turn, a more
                comprehensive understanding of the hazards human-made structures pose
                to the Kirtland's warbler. It is reasonable to presume, however, that
                more Kirtland's warblers collide with human-made structures than are
                reported.
                    Solutions to reduce the hazards that cause avian collisions with
                human-made structures are being implemented in many places.
                Extinguishing internal lights of buildings at night, avoiding the use
                of external floodlighting, and shielding the upward radiation of low-
                level lighting such as street lamps are expected to reduce attraction
                and trapping of birds within illuminated urban areas, and in turn,
                reduce injury and mortality caused by collision, predation, starvation,
                or exhaustion (reviewed in Ogden 1996, p. 31). The Service's Urban
                Conservation Treaty for Migratory Birds program has worked with several
                cities to adopt projects that benefit migrating birds flying through
                urban areas between breeding and wintering grounds. For example, some
                cities within the Kirtland's warbler's migration corridor, such as
                Chicago, Indianapolis, Columbus, Detroit, and Milwaukee, have ``Lights
                Out'' or similar programs, which encourage the owners and managers of
                tall buildings to turn off or dim exterior decorative lights, as well
                as interior lights, during spring and fall migration periods (National
                Audubon Society 2019,
                [[Page 54456]]
                entire). These programs are estimated to reduce general bird mortality
                by up to 83 percent (Field Museum 2007, p. 1).
                    Additionally, migrating birds are not equally attracted to various
                lighting patterns, and modifying certain types of lighting systems
                could significantly reduce collision-related mortality. Removing
                steady-burning, red L-810 lights and using only flashing, red L-864 or
                white L-865 lights on communication towers and other similarly lit
                aeronautical obstructions could reduce mortality rates by as much as 50
                to 70 percent (Gehring et al. 2009, p. 509). On December 4, 2015, the
                Federal Aviation Administration (FAA) revised its advisory circular
                that prescribes tower lighting to eliminate the use of L-810 steady-
                burning side lights on towers taller than 107 m (350 ft) (FAA Advisory
                Circular 70/7460-1L), and on September 28, 2016, it released
                specifications for flashing L-810 lights on towers 46-107 m (150-350
                ft) tall. These lighting changes should significantly reduce the risk
                of migratory bird collisions with communication towers.
                    As noted previously concerning potential threats to migratory
                habitat, if mortality during migration were limiting or likely to limit
                the population to the degree that maintaining a healthy population may
                be at risk, it should be apparent in the absence of the species from
                highly suitable breeding habitat in the core breeding range. In fact,
                we have seen just the opposite with increasing densities of breeding
                individuals in core areas and a range expansion into what would appear
                to be less suitable habitat elsewhere. This steady population growth
                and range expansion occurred while the potential threats to the species
                during migration were all increasing on the landscape (e.g., new
                communication towers and wind turbines).
                Synergistic Effects of Factors A Through E
                    When threats occur together, one may exacerbate the effects of
                another, causing effects not accounted for when threats are analyzed
                individually. Many of the threats to the Kirtland's warbler and its
                habitat discussed above under Factors A through E are interrelated and
                could be synergistic, and thus may cumulatively impact Kirtland's
                warbler beyond the extent of each individual threat. For example,
                increases in temperature and evaporation could reduce the amount of
                jack pine habitat available and increase the level of brood parasitism.
                Historically, habitat loss and brood parasitism significantly impacted
                the Kirtland's warbler and cumulatively acted to reduce its range and
                abundance. Today, these threats have been ameliorated and adequately
                minimized such that the species has exceeded the recovery goal. The
                best available data show a positive population trend over several
                decades and record high population levels. Continued habitat management
                and brown-headed cowbird control at sufficient levels, as identified in
                the Conservation Plan and at levels consistent with those to which
                management agencies committed in the MOU and MOA, will assure continued
                population numbers at or above the recovery criterion with the current
                magnitude of other threats acting on the Kirtland's warbler.
                Summary of Comments and Recommendations
                    In the proposed rule published on April 12, 2018 (83 FR 15758), we
                requested that all interested parties submit written comments on the
                proposal by July 11, 2018. We also contacted appropriate Federal and
                State agencies, scientific experts and organizations, and other
                interested parties and invited them to comment on the proposal.
                Newspaper notices inviting general public comment were published in The
                Milwaukee Journal Sentinel on April 16, 2018, and in The Detroit Free
                Press on April 23, 2018. We did not receive any requests for a public
                hearing. The draft Post-delisting Monitoring Plan (PDM) was made
                available on our website on June 7, 2018. During the comment period for
                the proposed rule, we received a total of 42 comment letters or
                statements directly addressing the proposed action. These included
                comments from seven peer reviewers and 34 comments from the public
                during the open comment period; all comments are posted on http://www.regulations.gov under Docket No. FWS-R3-ES-2018-0005. Many
                commenters expressed their support or opposition to the proposed rule
                without offering substantive information.
                    In accordance with our peer review policy published on July 1, 1994
                (59 FR 34270), we solicited expert opinion from 10 knowledgeable
                individuals with scientific expertise that included familiarity with
                Kirtland's warbler and its habitat, biological needs, and threats, as
                well as familiarity with conservation biology, ornithology, climate
                change, and population ecology. We received responses from seven peer
                reviewers. Almost all of the peer reviewers supported the proposed
                delisting rule, although one peer reviewer suggested that a more
                cautious approach would be to downlist the species to provide a
                ``buffer'' of protection. Many peer reviewers commented that the
                current status of Kirtland's warbler is accurately presented in the
                proposed rule.
                    We reviewed all comments we received from the peer reviewers and
                the public for substantive issues and new information regarding the
                delisting of Kirtland's warbler. Substantive comments we received
                during the comment period are addressed below and, where appropriate,
                are incorporated directly into this final rule. Comments that we
                received on the PDM without reference to or comment on the proposed
                rule are addressed separately in the PDM.
                    Comment (1): Several peer reviewers and public commenters expressed
                concern that additional funding will be needed to support the species
                post-delisting. They discussed the need for sufficient funding to
                ensure habitat management and brown-headed cowbird control will
                continue at levels necessary to support the population above the
                recovery goals. Several peer reviewers also mentioned that funding will
                be necessary to support monitoring efforts to ensure any significant
                changes to the species' population levels are detected. A reviewer also
                stated that an income-producing fund has been created and appears to be
                successful, but they were concerned over the uncertainty as to whether
                it will be adequate to support conservation efforts post-delisting.
                    Our Response (1): We acknowledge that the long-term survival of
                Kirtland's warbler is dependent upon the continued implementation of
                conservation programs that require agency commitment and sufficient
                funding. The vast majority of conservation programs (with the exception
                of brown-headed cowbird management) were previously funded through
                agency appropriations and grants, and not funded through ESA recovery
                funding. Thus, delisting Kirtland's warbler will not eliminate a major
                source of funding that is tied to its listing status. In the 2016 MOU,
                the MDNR, USFS, and Service reaffirmed their commitment to continue
                managing and monitoring Kirtland's warblers if the species is delisted.
                To supplement agency funding, which can fluctuate, the Kirtland's
                Warbler Alliance has been working with partners to establish additional
                funding sources for future conservation efforts. Recently, the American
                Bird Conservancy (ABC) was awarded a grant to help establish a long-
                term Kirtland's warbler endowment that would offset some of the
                agencies' costs and support future Kirtland's warbler
                [[Page 54457]]
                conservation throughout the bird's full life cycle (Graff 2018,
                unpaginated).
                    Previous funding of brown-headed cowbird management was provided
                through ESA funding; therefore, a new funding source is needed to
                secure brown-headed cowbird management efforts post-delisting. To
                address this, the MDNR and Service developed a dedicated fund to be
                used for brown-headed cowbird management and other high priority
                conservation needs. At the time the proposed delisting rule was
                published (83 FR 15758; April 12, 2018), the dedicated fund had greater
                than $1 million. Since then, an additional $1.1 million was added,
                increasing our certainty that sufficient funding for brown-headed
                cowbird management will be available in the future. This account is
                invested for long-term growth, and income generated will be used to
                ensure sufficient brown-headed cowbird management to adequately reduce
                brood parasitism of the Kirtland's warbler.
                    Comment (2): Several peer reviewers discussed the issue of brown-
                headed cowbird control. The majority expressed support of continuing
                the brown-headed cowbird management program and asked for more detail
                regarding how the agencies will monitor the rates of parasitism to know
                when parasitism rates change, how the agencies will respond to
                increases in parasitism rates, and whether sufficient funding exists to
                continue to support the brown-headed cowbird program at historical
                levels of trapping.
                    Our Response (2): Brood parasitism has historically been one of the
                primary threats to Kirtland's warbler, and thus the brown-headed
                cowbird management program has been a critical component of the
                recovery program. Recent research has shown a reduced brown-headed
                cowbird population throughout the Kirtland's warbler's core range in
                the northern Lower Peninsula. An experiment was initiated in 2015 to
                evaluate the effect of a reduced trapping program on Kirtland's warbler
                nest success. During a 3-year period (2015-2017), 3 of 385 Kirtland's
                warbler nests were parasitized in areas with a spatially reduced
                trapping program. Following these results, all trapping in the northern
                Lower Peninsula was suspended for the 2018 nesting season. In 2018,
                only one nest of over 140 was found to be parasitized. Additional
                information and data have been added to this final rule to reflect the
                most recent information on parasitism rates, including data from the
                2018 nesting season.
                    We fully expect brood parasitism rates to fluctuate and recognize
                that permanent reductions to the brown-headed cowbird management
                program are not prudent. Rather, an adaptive management approach is
                appropriate to ensure adequate brown-headed cowbird management into the
                future. We have included the need for continued research and monitoring
                in the PDM to help inform future efforts.
                    Based on the ongoing research, we do not expect that trapping
                levels will need to return to previous levels for several years, and
                may never return to historic levels. Through ongoing research, the KWCT
                hopes to establish trigger points that would dictate when trapping
                would be resumed and at what level. Through the MOA, and reaffirmed in
                a letter dated November 9, 2017, the MDNR has agreed to assume
                responsibility for the brown-headed cowbird management program. Funding
                for the brown-headed cowbird management program will be available
                through interest accrued from the brown-headed cowbird dedicated fund
                (see our response to Comment (1)), or other agency funds through the
                MDNR.
                    External funding has been secured for the Smithsonian Migratory
                Bird Center to continue monitoring brown-headed cowbird presence and
                brood parasitism for the 2019 and 2020 nesting seasons. The results
                from the cowbird monitoring research conducted during 2015-2020 will be
                used to develop specific monitoring protocols that will be conducted in
                accordance with the PDM. We also expect the KWCT to continue assessing
                the need for further monitoring or research.
                    Comment (3): Several peer reviewers discussed the importance of
                continued habitat management for the Kirtland's warbler population. A
                reviewer asserted that we made a major assumption in stating that
                management agencies will continue to create habitat post-delisting.
                Another comment discussed the uncertainty regarding timber
                marketability and the importance of timber receipts in offsetting the
                cost of Kirtland's warbler habitat management, and asked that this
                topic be more explicitly addressed in the rule. Further, a reviewer
                recommended a better plan on developing forestry techniques that
                increase marketability of the timber, as well as finding creative ways
                to fund future habitat management efforts. Many of the comments
                received regarding continued habitat management related to ensuring
                management would continue and how habitat management will be funded.
                    Our Response (3): The management agencies have a long-standing
                history of providing habitat for the Kirtland's warbler and have
                described their commitment to continuing management for the Kirtland's
                warbler in the Conservation Plan and the MOU. We recognize the
                uncertainty over future timber markets and the impact that timber
                receipts may have in offsetting the costs of habitat management. The
                land managers and the KWCT have also recognized this uncertainty and
                have started the process to develop and test alternative planting
                techniques that would reduce costs and improve the marketability of
                jack pine through increased growth rates while still providing
                Kirtland's warbler nesting habitat. Currently, the Conservation Plan
                indicates up to 25 percent of future habitat management, annually, may
                incorporate non-traditional regeneration techniques designed to address
                the marketability and regeneration of jack pine.
                    Specific plans are not yet available, as the habitat management
                planning process is dynamic. Alternative management techniques will
                evolve over time and be adaptable to changing circumstances. A
                subcommittee of the KWCT has routinely met over the last several years
                to develop alternative techniques. Additional information regarding
                timber marketability and future jack pine regeneration techniques has
                been added to this rule.
                    Habitat management will continue to be funded through appropriated
                funds provided to the land management agencies for timber harvest and
                reforestation. Additional funds may be available through the endowment
                being developed by the Kirtland's Warbler Alliance and ABC, which is
                described earlier in this rule.
                    Comment (4): Several peer reviewers provided comments on the
                Conservation Plan's allowance of up to 25 percent of habitat management
                to be non-traditional habitat regeneration techniques. They stated that
                the quality of Kirtland's warbler breeding habitat created through new
                techniques is not known and could result in a loss of up to 25 percent
                of breeding habitat and potentially a substantial decrease in the
                abundance of Kirtland's warbler. The reviewers recommend any non-
                traditional techniques be used as part of the annual habitat goals only
                after they have been shown to be effective. They clarified that both
                density of breeding pairs and fledgling production are important
                metrics for evaluating the quality of non-traditional breeding habitat.
                Another peer reviewer asked us to emphasize that the 25 percent
                experimental habitat regeneration is a maximum and should not be
                interpreted as an annual requirement. This reviewer also pointed out
                that the 75 percent of
                [[Page 54458]]
                breeding habitat created using traditional methods is enough to support
                the population above the recovery goal of 1,000 pairs and reflects the
                best available science regarding breeding habitat use by the species.
                    Our Response (4): We have clarified in this rule that the 25
                percent experimental habitat amount is a maximum amount annually.
                Managing habitat with traditional techniques at a minimum of 75 percent
                of the annual objective will still provide enough breeding habitat to
                maintain the species well above the recovery goal. Additionally, we
                expect that the experimental habitat will still provide breeding
                habitat for Kirtland's warbler but at potentially lower densities or
                reduced nest success. These experimental designs will be closely
                monitored to evaluate their effectiveness in regenerating jack pine and
                providing Kirtland's warbler breeding habitat.
                    Comment (5): Several peer reviewers also commented on the agencies'
                commitment to continue conservation actions for Kirtland's warbler and
                whether the level of commitment provided via the current MOA and MOU
                are sufficient to support delisting. A peer reviewer expressed concern
                regarding the level of commitment to continuing habitat management and
                pointed out that the MOU indicates that management will occur ``only as
                appropriated funds are available'' and that ``additional funds will be
                necessary to meet these commitments.'' They also pointed out that the
                MOU can be terminated at any time by any agency and asked whether the
                agreements are legally binding. Multiple peer reviewers and several
                public commenters indicated that the levels of commitment in the
                existing MOU and MOA are sufficient to support delisting. One reviewer
                asked if the MOU had expired and, if so, when it might be renewed.
                Regarding conservation agreements on the wintering grounds, one
                reviewer commented that they are not necessary prior to delisting,
                given our understanding of threats to winter habitat.
                    Our Response (5): The MOU is a synthesis of the land management
                agencies' commitments to forest management, developed under the
                requirements of Federal and State law that will remain in effect after
                delisting, to sustain Kirtland's warbler. The MOU was first signed in
                2011, was renewed in 2016, and currently expires in 2020. Prior and
                subsequent to the MOU, habitat management and other conservation
                programs were always dependent on annual appropriated funds provided to
                the land management agencies. Further, MDNR did not have any legal
                obligations under the ESA to conduct habitat management during the last
                40 years while the species was listed, but MDNR adopted into their
                forest plans the habitat management goals set forth by the Kirtland's
                Warbler Recovery Team and later by the KWCT. The MOA is specific to
                cowbird management and the development of a dedicated funding source
                primarily for that activity, but possibly other activities in the
                future if excess funding resources become available. The MOA was signed
                in 2015 with no expiration date and stipulates that the Service and
                MDNR will review progress under the MOA every 5 years to determine
                whether any modifications are warranted. While not fully legally
                binding, the MOU and MOA are built on a foundation of Federal and State
                law guiding land management and further express the agencies'
                commitments to continue managing for the species, regardless of the
                species' status under the ESA.
                    Comment (6): Several peer reviewers asked for additional detail
                regarding the intensity and extent of population monitoring post-
                delisting. A peer reviewer expressed concern over the lack of full
                surveys (censuses) in recent years, noting that the last full
                population survey was in 2015. Several reviewers questioned the recent
                (2016) shift from full census to the less intensive survey effort and
                requested that the MDNR sampling method be better explained. Several
                peer reviewers indicated that MDNR should continue with the full census
                until the proposed survey technique undergoes peer review and
                publication in a reputable journal. One peer reviewer emphasized that
                any reduced survey effort should be capable of providing a reliable
                extrapolation of total breeding male abundance, so as to allow
                comparison with past total singing/territorial male counts from
                previous population censuses. Another reviewer commented that the
                census techniques should be improved to assure accuracy, reduce
                uncertainty, and improve ability to detect small population-level
                changes. In addition, a reviewer noted that in areas where reduced
                brown-headed cowbird trapping occurs (as compared to previous levels)
                or experimental habitat management techniques are used, more intensive
                population monitoring is necessary. Some reviewers also suggested that
                the PDM should include monitoring of survival and reproductive success
                in addition to the number of singing males. Furthermore, one peer
                reviewer mentioned the possibility of using mist-netting as an
                alternative to nest searching to estimate productivity.
                    Our Response (6): We appreciate the comments regarding the need for
                further details on how the Kirtland's warbler population will continue
                to be monitored post-delisting. Our knowledge of the Kirtland's warbler
                population and its response to habitat management has greatly been
                informed by conducting an annual census using similar protocols over
                several decades. We recognize that the complexity of conducting an
                annual census has changed as the species has expanded from its core
                breeding range. Further, the intensity of a monitoring effort should be
                continually reevaluated in accordance with adaptive management needs
                and the population size (e.g., for a smaller population, intensive
                monitoring is more feasible and potentially more important). For a
                recovered population, unless new information or concerns suggest
                otherwise, a less-intensive monitoring effort (when compared to when
                populations were critically imperiled) helps ensure staffing and
                funding resources are used most effectively. Monitoring of the
                Kirtland's warbler has routinely been coordinated by the respective
                land management agencies in coordination with the Service and Recovery
                Team, or more recently, the KWCT. As the species' population and range
                has expanded, so has the time and resources needed to conduct a full
                census. While the KWCT recognizes how critically important it is to
                continue monitoring the species, it has also recognized that there may
                be more efficient ways to monitor the species' status than a full
                census.
                    In 2016, Michigan State University, in conjunction with MDNR,
                developed a survey protocol designed to detect a 20 percent change in
                the population. The recommended survey would randomly select 50 percent
                of occupied stands on which the standard census protocol would be
                conducted. By incorporating stand size and age with the observed number
                of singing males, the survey would provide an estimate of the singing
                male population with enough confidence to detect a 20 percent reduction
                in individual singing males. The survey design was tested by using
                previous census results from 2010, 2011, 2012, and 2013. In each case,
                the reported census number fell within the survey protocols' 95%
                confidence interval. Other land management agencies, including USFS and
                WDNR, plan to continue periodic full censuses.
                    We recognize that there may be instances where more precise
                population monitoring is warranted.
                [[Page 54459]]
                When experimenting with alternative habitat regeneration techniques or
                reduced brown-headed cowbird management levels, a higher level of
                monitoring would need to be conducted in order to accurately determine
                the warbler's response to those activities. The need for additional
                monitoring will be determined by the management agencies, researchers,
                and KWCT. This need is also addressed within the PDM.
                    We believe that the monitoring proposed in the PDM is sufficient to
                detect population-level trends, and MDNR's proposed sampling technique
                will provide a sufficient estimate of the singing male population. The
                KWCT will continue to evaluate monitoring protocols and may determine
                that a periodic full census may be warranted as time and resources
                allow.
                    Comment (7): A peer reviewer asked for clarification on the
                population level that will trigger intensified conservation efforts
                necessary to ensure the population remains above the numerical recovery
                goal of 1,000 pairs. Another emphasized that maintaining population
                numbers above the recovery goal provides flexibility (and a buffer) if
                new threats emerge.
                    Our Response (7): In development of the Conservation Plan, the
                agencies agreed that if the population drops below 1,300 singing males,
                they would discuss the population decline, decide whether their
                objectives and actions need to be changed, and implement these
                recommended changes. The primary objective remains to keep the
                Kirtland's warbler population above the numerical recovery goal of
                1,000 pairs. However, any noted decline from current population levels
                will be discussed amongst the agencies and the KWCT, and any
                appropriate action will be taken.
                    Comment (8): Several reviewers commented that a better
                understanding of wintering habitat needs should be a high priority for
                the KWCT and recommended fully mapping the extent of wintering habitat,
                as well as further research on how various activities and land uses on
                the wintering grounds impact the species.
                    Our Response (8): Although threats to Kirtland's warblers on the
                wintering grounds exist, the current extent and magnitude of these
                threats are not significantly limiting Kirtland's warbler population
                numbers, based on the species' continuous population growth over the
                last two decades. If the population shows signs of decline in the
                future, we will coordinate with the KWCT to assess all potential
                stressors, including those occurring on the wintering grounds. The KWCT
                and its Non-breeding Range Subcommittee recognize the importance of
                continued research on the needs of the Kirtland's warbler on the
                wintering grounds, specifically delineating wintering habitat and
                assessing how land use may impact the species.
                    Comment (9): Multiple peer reviewers commented on the species'
                wintering distribution, and provided citations to incorporate into the
                rule. One reviewer added that occasional vagrant Kirtland's warbler
                sightings outside of the core islands should not give the impression
                that suitable habitat is widespread elsewhere in the Caribbean; the
                rule should be explicit about our ignorance regarding suitable habitat
                elsewhere (outside of the core), as habitat suitability has not yet
                been measured except for on Eleuthera Island.
                    Our Response (9): The text under Distribution in this rule has been
                updated to more clearly reflect this uncertainty regarding wintering
                distribution.
                    Comment (10): Several comments received were related to our
                analysis of the effects of climate change on the Kirtland's warbler's
                breeding and wintering grounds. Two reviewers stated that the analysis
                of climate change in the proposed rule was thorough and relied on the
                best available science. One reviewer stated that delisting will not
                prohibit the ongoing research to improve our understanding of future
                potential threats. Another peer reviewer commented that current climate
                change projections indicate that habitat suitability within the core
                breeding range will remain suitable for supporting jack pine in this
                century; another commenter stated that climate change could result in a
                shift in the range toward Wisconsin. One reviewer mentioned that on the
                wintering grounds, Kirtland's warbler could be negatively affected by
                climate change, but added that there is much uncertainty and currently
                a lack of strong evidence to suggest a major loss or degradation of
                wintering grounds habitat will occur in the near future. Another
                reviewer emphasized the importance of acquiring baseline data on
                wintering habitat availability and quality to provide a context for
                future climate change analysis. A reviewer commented that climate
                change projections that predict an increased drought for the central
                islands of The Bahamas may represent risk to the main wintering area
                and recommended protecting drought-tolerant sites (e.g., freshwater
                lens near the ground surface) where the Kirtland's warbler's preferred
                fruit plants occur. Another reviewer provided the citation for a
                recently published paper regarding future risks of heavy rainfall
                events and extended periods of hurricane-force winds due to an
                increasing trend for hurricanes to have decreased forward or
                translational speeds (Kossin 2018, entire). Further, the reviewer asked
                that the rule be updated to add observations of hurricane effects on
                the island of San Salvador, where post-hurricane declines of Kirtland's
                warblers have been observed.
                    Our Response (10): Climate change predictions are variable and in
                many cases uncertain. We reviewed the best available data using
                multiple models and emission scenarios to evaluate the impact of
                climate change on the Kirtland's warbler in the foreseeable future. On
                the breeding grounds, temperature will very likely increase, and
                precipitation will increase for parts of the year but may decrease at
                the end of the growing season (Handler et al. 2014, pp. 72-75; Janowiak
                et al. 2014, pp. 66-85). On the wintering grounds, temperatures will
                also increase, which could result in rising sea level. The Caribbean is
                experiencing a general drying trend, but there is temporal and spatial
                variation.
                    We will remain engaged with the KWCT and its Non-breeding Range
                Subcommittee to monitor climate conditions and how they may impact the
                Kirtland's warbler. We will also work with the KWCT as they engage The
                Bahamas National Trust and other groups in an effort to identify and
                protect critical sites in The Bahamas for Kirtland's warbler
                conservation.
                    Additional discussion regarding the potential for climate change
                has been added to this rule under Factor E: Climate Change.
                    Comment (11): Almost all of the peer reviewers indicated their
                support of delisting the Kirtland's warbler and stated that the
                analysis in the proposed rule was sufficient to support delisting. Many
                heralded the Kirtland's warbler as a success story of the ESA. One peer
                reviewer, however, recommended we apply a more cautious approach and
                instead reclassify (i.e., downlist) Kirtland's warbler as a threatened
                species. Several public commenters had similar comments indicating that
                the proposed delisting rule was premature, and we should maintain
                protections to ensure we more fully understand proposed and recent
                changes to habitat management and brown-headed cowbird control programs
                before changing the status of the Kirtland's warbler.
                    Our Response (11): During our analysis, we evaluated the status of
                the
                [[Page 54460]]
                Kirtland's warbler to determine if the species met the definition of an
                endangered or threatened species based on any of five factors: (A) The
                present or threatened destruction, modification, or curtailment of its
                habitat or range; (B) overutilization for commercial, recreational,
                scientific, or educational purposes; (C) disease or predation; (D) the
                inadequacy of existing regulatory mechanisms; or (E) other natural or
                manmade factors affecting its continued existence. Based on the status
                of the species and the known and foreseeable threats, we determined
                that the species has recovered and does not meet the ESA's definition
                of an endangered or a threatened species. Thus, the Kirtland's warbler
                does not warrant listing under the ESA. While we appreciate the concern
                and suggestion of a more cautious approach, delisting Kirtland's
                warbler is warranted based on the best available information.
                    Comment (12): One peer reviewer expressed concern over potential
                forest pests causing a catastrophic loss of suitable habitat; the
                reviewer acknowledges that the currently known insect or fungal threats
                to jack pine or red pine are possible to manage, and forests in this
                region are under the oversight of forest management agencies. The
                reviewer added that the Kirtland's warbler may be less vulnerable to
                catastrophic loss due to pests or disease outbreaks when compared to
                historically lower population levels. One commenter expressed concern
                over the effects of pesticides on the Kirtland's warbler and its insect
                prey.
                    Our Response (12): Our review of the best available science did not
                identify any known threats to the status of the Kirtland's warbler from
                forest pests, disease, or the use of pesticides. We acknowledge that
                new threats from insects, fungi, other pests, or the use of a new
                pesticide may emerge in the future, but our analysis concluded that the
                species has good redundancy, representation, and resiliency, which
                should allow the species to withstand potential future stressors.
                    We agree with the reviewer that the management of forest pests and
                disease primarily falls under the authority of the forest management
                agencies. Through collaborative efforts, the KWCT and its Breeding
                Range Subcommittee, the land management agencies' silviculturists, and
                the forest product industry can collectively monitor these potential
                threats and respond accordingly if the threats are determined to impact
                Kirtland's warbler nesting habitat.
                    We added additional discussion and references regarding forest
                pests, disease, and pesticides to this rule (see discussions under
                Factors A and E).
                    Comment (13): A peer reviewer requested that additional discussion
                be added regarding recreation, access, and development, including
                current restrictions in areas occupied by the Kirtland's warbler, and
                regarding changes that would occur if the Kirtland's warbler is
                delisted. The reviewer expressed concern that unrestricted recreational
                activity and nearby development could have unforeseen impacts on the
                population and that this should be more explicitly considered in our
                analysis.
                    Our Response (13): Currently, only a portion of the Kirtland's
                warbler's nesting habitat in the northern Lower Peninsula is posted
                closed during the species' breeding season by the respective land
                management agency. Many of the recreational uses of the Kirtland's
                warbler's nesting habitat (e.g., hunting, blueberry picking) are
                typically conducted at times when impacts to the species are limited.
                Further, in areas that are not posted closed, we have not seen evidence
                of impacts to the species. Delisting Kirtland's warbler would not limit
                the authority of the land management agencies to close areas as needed
                to limit resource damage or protect sensitive species. We added
                additional information and discussion related to other uses of the
                Kirtland's warbler's nesting habitat to this rule (see Factor B
                discussion).
                    Comment (14): Several peer reviewers provided additional
                information and suggested additional references to support statements
                in the proposed rule. This included information regarding mortality due
                to lighted cruise ships in the Caribbean, presence of other avian brood
                parasites (i.e., cuckoo species) in the Kirtland's warbler breeding
                range, and new information on wintering habitat and distribution.
                    Our Response (14): We appreciate the additional information
                provided by the reviewers. We reviewed the additional information and
                corresponding references, and we updated this final rule accordingly.
                    Comment (15): A peer reviewer suggested adding a discussion of
                reproductive rates to the ``Demographics'' section of the rule.
                    Our Response (15): We added this discussion as suggested.
                    Comment (16): A peer reviewer commented that the assumption
                regarding number of singing males equating to number of breeding pairs
                needs clarification and suggested caution when interpreting the number
                of singing males as an indication of number of breeding pairs.
                    Our Response (16): We added additional clarification to this rule
                under Abundance and Population Trends.
                    Comment (17): One commenter requested peer review and a public
                comment period greater than or equal to 90 days.
                    Our Response (17): The proposed rule was open for public comments
                for 90 days, from April 12, 2018, through July 11, 2018, and we
                solicited peer review on the proposal.
                    Comment (18): One commenter asked for additional detail on State
                regulatory protections if the Kirtland's warbler is delisted.
                    Our Response (18): The Kirtland's warbler is currently protected by
                State law in a number of States in the species' breeding and migratory
                ranges under the respective State endangered species regulations.
                Changing the Federal status of the Kirtland's warbler will not
                automatically change the listing status of the Kirtland's warbler under
                State law. Each State evaluates the current status of a species to
                determine whether it warrants protection under the State's respective
                statutes. We expect that each State will evaluate the State listing
                status of the Kirtland's warbler at some point in the next several
                years, but we cannot speculate as to their decisions under State law.
                Similarly, the Kirtland's warbler is also protected as endangered under
                Canada's Species at Risk Act of 2003. Canadian officials will decide
                whether to retain protected status for the Kirtland's warbler based on
                their laws and regulations.
                    Comment (19): One commenter asked if we were proposing delisting to
                benefit the wind industry and suggested the proposed rule was motivated
                by reducing regulatory burden to make it easier to get ``wind towers in
                place in rural Ohio.''
                    Our Response (19): Our determination is based solely on the status
                of the species utilizing the best available science, and our status
                review was initiated due to the species' population and range expansion
                in recent years, the development of the Kirtland's Warbler Conservation
                Plan and MOU, and development of a long-term endowment and MOA to
                conduct brown-headed cowbird management.
                Determination
                    Section 4 of the ESA (16 U.S.C. 1533), and its implementing
                regulations at 50 CFR part 424, set forth the procedures for
                determining whether a species is an endangered species or threatened
                species and should be included on the Federal Lists of Endangered and
                Threatened Wildlife and Plants. The
                [[Page 54461]]
                ESA defines an endangered species as any species that is ``in danger of
                extinction throughout all or a significant portion of its range'' and a
                threatened species as any species that is ``likely to become an
                endangered species within the foreseeable future throughout all or a
                significant portion of its range.''
                    Under section 4(a)(1) of the ESA, we determine whether a species is
                an endangered species or threatened species because of any of the
                following factors: (A) The present or threatened destruction,
                modification, or curtailment of its habitat or range; (B)
                overutilization for commercial, recreational, scientific, or
                educational purposes; (C) disease or predation; (D) the inadequacy of
                existing regulatory mechanisms; or (E) other natural or manmade factors
                affecting its continued existence. These same factors apply whether we
                are analyzing the species' status throughout all of its range or
                throughout a significant portion of its range.
                Determination of Status Throughout All of the Kirtland's Warbler's
                Range
                    We have carefully assessed the best scientific and commercial
                information available regarding the past, present, and future threats
                to the Kirtland's warbler. We assessed the five factors to evaluate
                whether the species is in danger of extinction, or likely to become so
                in the foreseeable future, throughout all of its range. The size of the
                Kirtland's warbler population is currently at its known historical
                maximum, which is nearly 10 times larger than it was at the time of
                listing and more than double the recovery goal. The population's
                breeding range also expanded outside of the northern Lower Peninsula to
                areas in Michigan's Upper Peninsula, Wisconsin, and Ontario. This
                recovery is attributable to successful interagency cooperation in the
                management of habitat and brood parasitism. The amount of suitable
                habitat has increased by approximately 150 percent since listing,
                primarily due to the increased amount of planted habitat generated from
                adaptive silvicultural techniques. Brown-headed cowbird control has
                been conducted on an annual basis within the majority of Kirtland's
                warbler nesting areas since 1972, and has greatly reduced the impacts
                of brood parasitism.
                    During our analysis, we found that impacts believed to be threats
                at the time of listing have been eliminated or reduced, or are being
                adequately managed since listing, and we do not expect any of these
                conditions to substantially change after delisting and into the
                foreseeable future. Population modeling that assessed the long-term
                population viability of Kirtland's warbler populations showed stable
                populations over a 50-year simulation period with current habitat
                management and maintaining sufficient brown-headed cowbird removal (see
                Population Viability, above). Brood parasitism and availability of
                sufficient suitable breeding habitat are adequately managed through the
                Kirtland's Warbler Breeding Range Conservation Plan and the 2016 MOU.
                The Conservation Plan and the MOU acknowledge the conservation-reliant
                nature of the Kirtland's warbler and the need for continued habitat
                management and brown-headed cowbird control, and affirm that the
                necessary long-term management actions will continue. The species is
                resilient to threats including changing weather patterns and sea level
                rise due to the effects of climate change, collision with lighted and
                human-made structures, impacts to wintering and migratory habitat, and
                cumulative effects, and existing information indicates that this
                resilience will not change in the foreseeable future. These conclusions
                are supported by the available information regarding the species'
                abundance, distribution, and trends. Thus, after assessing the best
                available information, we conclude that the Kirtland's warbler is not
                in danger of extinction throughout all of its range, nor is it likely
                to become so within the foreseeable future.
                Determination of Status Throughout a Significant Portion of the
                Kirtland's Warbler's Range
                    Under the ESA and our implementing regulations, a species may
                warrant listing if it is in danger of extinction or likely to become so
                in the foreseeable future throughout all or a significant portion of
                its range (SPR). Where the best available information allows the
                Service to determine a status for the species rangewide, that
                determination should be given conclusive weight because a rangewide
                determination of status more accurately reflects the species' degree of
                imperilment and better promotes the purposes of the ESA. Under this
                reading, we should first consider whether the species warrants listing
                ``throughout all'' of its range and proceed to conduct a ``significant
                portion of its range'' analysis if, and only if, a species does not
                qualify for listing as either an endangered or a threatened species
                according to the ``throughout all'' language.
                    Having determined that the Kirtland's warbler is not in danger of
                extinction or likely to become so in the foreseeable future throughout
                all of its range, we now consider whether it may be in danger of
                extinction or likely to become so in the foreseeable future in an SPR.
                The range of a species can theoretically be divided into portions in an
                infinite number of ways, so we first screen the potential portions of
                the species' range to determine if there are any portions that warrant
                further consideration. To do the ``screening'' analysis, we ask whether
                there are portions of the species' range for which there is substantial
                information indicating that: (1) The portion may be significant; and
                (2) the species may be, in that portion, either in danger of extinction
                or likely to become so in the foreseeable future. For a particular
                portion, if we cannot answer both questions in the affirmative, then
                that portion does not warrant further consideration and the species
                does not warrant listing because of its status in that portion of its
                range. We emphasize that answering these questions in the affirmative
                is not a determination that the species is in danger of extinction or
                likely to become so in the foreseeable future throughout a significant
                portion of its range--rather, it is a step in determining whether a
                more detailed analysis of the issue is required.
                    If we answer these questions in the affirmative, we then conduct a
                more thorough analysis to determine whether the portion does indeed
                meet both of the SPR prongs: (1) The portion is significant; and (2)
                the species is, in that portion, either in danger of extinction or
                likely to become so in the foreseeable future. Confirmation that a
                portion does indeed meet one of these prongs does not create a
                presumption, prejudgment, or other determination as to whether the
                species is an endangered species or threatened species. Rather, we must
                then undertake a more detailed analysis of the other prong to make that
                determination. Only if the portion does indeed meet both SPR prongs
                would the species warrant listing because of its status in a
                significant portion of its range.
                    At both stages in this process--the stage of screening potential
                portions to identify any portions that warrant further consideration
                and the stage of undertaking the more detailed analysis of any portions
                that do warrant further consideration--it might be more efficient for
                us to address the ``significance'' question or the ``status'' question
                first. Our selection of which question to address first for a
                particular portion depends on the biology of the species, its range,
                and the threats it faces. Regardless of which question we address
                first, if we reach a negative answer with respect to the first question
                [[Page 54462]]
                that we address, we do not need to evaluate the second question for
                that portion of the species' range.
                    For the Kirtland's warbler, we chose to evaluate the status
                question (i.e., identifying portions where the Kirtland's warbler may
                be in danger of extinction or likely to become so in the foreseeable
                future) first. To conduct this screening, we considered whether the
                threats are geographically concentrated in any portion of the species'
                range at a biologically meaningful scale.
                    Kirtland's warblers occupy different geographic areas (breeding
                grounds, migratory routes, wintering grounds) throughout the course of
                a year. Although there are different threats acting on the species on
                the breeding grounds, migratory routes, and wintering grounds (see
                discussion under Factors A through E, above), the threats associated
                with these areas are uniformly spread across each area (e.g., threats
                on the breeding grounds are uniform across the breeding range, threats
                on the wintering grounds are uniform across the winter range). The
                entire population moves through the full annual cycle (breeding,
                migration, and wintering) and functions as a single panmictic
                population (see discussion under ``Genetics,'' above); therefore, these
                different geographic areas do not represent biologically separate
                populations that could be exposed to different threats.
                    We examined the following threats: Availability and distribution of
                breeding, migration, and wintering habitat; pesticides; brood
                parasitism; the effects of climate change; collision with lighted and
                human-made structures; and the cumulative effects of these threats. We
                found no concentration of threats in any portion of the Kirtland's
                warbler's range at a biologically meaningful scale. If both (1) a
                species is not in danger of extinction or likely to become so in the
                foreseeable future throughout all of its range and (2) the threats to
                the species are essentially uniform throughout its range, then the
                species could not be in danger of extinction or likely to become so in
                the foreseeable future in any biologically meaningful portion of its
                range. For the Kirtland's warbler, we found both: The species is not in
                danger of extinction or likely to become so in the foreseeable future
                throughout all of its range, and there is no geographical concentration
                of threats so the threats to the species are essentially uniform
                throughout its range. Therefore, no portions warrant further
                consideration through a more detailed analysis, and the species is not
                in danger of extinction or likely to become so in the foreseeable
                future in any significant portion of its range. Our approach to
                analyzing SPR in this determination is consistent with the court's
                holding in Desert Survivors v. Department of the Interior, No. 16-cv-
                01165-JCS, 2018 WL 4053447 (N.D. Cal. Aug. 24, 2018).
                    Our review of the best available scientific and commercial
                information indicates that the Kirtland's warbler is not in danger of
                extinction or likely to become an endangered species within the
                foreseeable future throughout all or a significant portion of its
                range. Therefore, we find that listing the Kirtland's warbler as an
                endangered species or a threatened species under the ESA is not
                warranted at this time.
                Conclusion
                    We have carefully assessed the best scientific and commercial
                information available regarding the past, present, and future threats
                to the Kirtland's warbler. The threats that led to the species being
                listed under the ESA (i.e., primarily loss of the species' habitat
                (Factor A) and effects of brood parasitism by brown-headed cowbirds
                (Factor E)) have been removed, have been ameliorated, or have been
                appropriately managed by the actions of multiple conservation partners
                over the past 50 years. These actions include habitat management,
                brown-headed cowbird control, monitoring, research, and education.
                Given commitments shown by the cooperating agencies entering into the
                Kirtland's warbler MOU and the long record of engagement and proactive
                conservation actions implemented by the cooperating agencies over a 50-
                year period, we expect conservation efforts will continue to support a
                healthy, viable population of the Kirtland's warbler post-delisting and
                into the foreseeable future. Furthermore, there is no information to
                conclude that, at any time over the next 50-year window (as we define
                the foreseeable future for this species), the species will be in danger
                of extinction. Thus, we have determined that none of the existing or
                potential threats, either alone or in combination with others, is
                likely to cause the Kirtland's warbler to be in danger of extinction
                throughout all or a significant portion of its range, nor are any of
                the existing or potential threats likely to cause the species to become
                endangered within the foreseeable future throughout all or a
                significant portion of its range. On the basis of our evaluation, we
                conclude that, due to recovery, the Kirtland's warbler is not an
                endangered or threatened species. We, therefore, remove the Kirtland's
                warbler from the Federal List of Endangered and Threatened Wildlife at
                50 CFR 17.11(h) due to recovery.
                Effects of This Rule
                    This rule revises 50 CFR 17.11(h) by removing the Kirtland's
                warbler from the Federal List of Endangered and Threatened Wildlife. On
                the effective date of this rule (see DATES, above), the prohibitions
                and conservation measures provided by the ESA, particularly through
                sections 7 and 9, no longer apply to this species. Federal agencies are
                no longer required to consult with the Service under section 7 of the
                ESA in the event that activities they authorize, fund, or carry out may
                affect the Kirtland's warbler. There is no critical habitat designated
                for this species; therefore, this rule does not affect 50 CFR 17.95.
                Removal of the Kirtland's warbler from the List of Endangered and
                Threatened Wildlife does not affect the protection given to all
                migratory bird species under the MBTA.
                Post-Delisting Monitoring
                    Section 4(g)(1) of the ESA requires us, in cooperation with the
                States, to implement a system to monitor for not less than 5 years the
                status of all species that have been recovered and delisted. The
                purpose of this requirement is to develop a program that detects the
                failure of any delisted species to sustain itself without the
                protective measures provided by the ESA. If, at any time during the
                monitoring period, data indicate that protective status under the ESA
                should be reinstated, we can initiate listing procedures, including, if
                appropriate, emergency listing.
                    The PDM for the Kirtland's warbler was developed in coordination
                with our Federal, State, and other partners. The PDM is based upon
                current research and effective management practices that have improved
                the status of the species since listing. Ensuring continued
                implementation of proven management strategies, such as brown-headed
                cowbird control and habitat management, that have been developed to
                sustain the species is a fundamental goal of the PDM. The PDM
                identifies measurable management thresholds and responses for detecting
                and reacting to significant changes in the Kirtland's warbler's
                numbers, distribution, and persistence. If declines are detected
                equaling or exceeding these thresholds, the Service, in combination
                with other PDM participants, will investigate causes of these declines.
                The investigation will be to determine if the Kirtland's warbler
                warrants expanded monitoring, additional research, additional habitat
                protection or brood
                [[Page 54463]]
                parasite management, or resumption of Federal protection under the ESA.
                For example, monitoring Kirtland's warbler singing males, annual
                habitat management acres, and brown-headed cowbird abundance or
                parasitism rates will inform partners on the Kirtland's warbler's
                status. If the population falls below 1,300 pairs, this would trigger
                the partners to (1) schedule a meeting, (2) discuss what is causing the
                decline, (3) decide how to respond, and (4) implement the recommended
                changes. The PDM requires census or selectively sampling the Kirtland's
                warbler breeding population every other year for a period of 12 years.
                The final PDM plan is available at https://www.fws.gov/midwest/Endangered/birds/Kirtland.
                Required Determinations
                National Environmental Policy Act
                    We determined that we do not need to prepare an environmental
                assessment or an environmental impact statement, as defined under the
                authority of the National Environmental Policy Act of 1969 (42 U.S.C.
                4321 et seq.), in connection with regulations adopted pursuant to
                section 4(a) of the ESA. We published a notice outlining our reasons
                for this determination in the Federal Register on October 25, 1983 (48
                FR 49244).
                Government-to-Government Relationship With Tribes
                    In accordance with the President's memorandum of April 29, 1994,
                ``Government-to-Government Relations with Native American Tribal
                Governments'' (59 FR 22951), Executive Order 13175, Secretarial Order
                3206, the Department of the Interior's manual at 512 DM 2, and the
                Native American Policy of the Service, January 20, 2016, we readily
                acknowledge our responsibility to communicate meaningfully with
                recognized Federal Tribes on a government-to-government basis. We
                contacted the tribes in the Midwest within the range of the Kirtland's
                warbler and requested their input and comments on the proposed
                delisting rule.
                References Cited
                    A complete list of all references cited in this rule is available
                at http://www.regulations.gov under Docket No. FWS-R3-ES-2018-0005 or
                upon request from the Field Supervisor, Michigan Ecological Services
                Field Office (see FOR FURTHER INFORMATION CONTACT).
                Authors
                    The primary authors of this rule are staff members of the Michigan
                Ecological Services Field Office in East Lansing, Michigan, in
                coordination with the Midwest Regional Office in Bloomington,
                Minnesota.
                List of Subjects in 50 CFR Part 17
                    Endangered and threatened species, Exports, Imports, Reporting and
                recordkeeping requirements, Transportation.
                Regulation Promulgation
                    Accordingly, we amend part 17, subchapter B of chapter I, title 50
                of the Code of Federal Regulations, as set forth below:
                PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS
                0
                1. The authority citation for part 17 continues to read as follows:
                    Authority: 16 U.S.C. 1361-1407; 1531-1544; 4201-4245, unless
                otherwise noted.
                Sec.  [thinsp]17.11  [Amended]
                0
                2. Amend Sec.  [thinsp]17.11 in the table in paragraph (h) by removing
                the entry for ``Warbler (wood), Kirtland's'' under ``BIRDS'' from the
                List of Endangered and Threatened Wildlife.
                    Dated: August 29 2019.
                Stephen Guertin,
                Principal Deputy Director, U.S. Fish and Wildlife Service, Exercising
                the Authority of the Director, U.S. Fish and Wildlife Service.
                [FR Doc. 2019-22096 Filed 10-8-19; 8:45 am]
                BILLING CODE 4333-15-P